A novel properties of rice bran: rice bran supplement alleviates chronic restraint stress-induced depression-like behaviors in mice

doi:10.21203/rs.3.rs-3212537/v1

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A novel properties of rice bran: rice bran supplement alleviates chronic restraint stress-induced depression-like behaviors in mice

https://doi.org/10.21203/rs.3.rs-3212537/v1

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Depression is emerging as a social and health-related issue in many countries. Rice bran supplement (RBS) possesses a variety of biological properties; however, its potential antidepressant effects have not been previously reported. This study investigated the antidepressant effects of RBS in a mouse model of chronic restraint stress (CRS)-induced depression. RBS (250, 500, and 1000 mg/kg) was administered to mice subjected to CRS for 5 weeks. RBS significantly improved depressive symptoms in CRS-exposed mice, as evidenced by increased sucrose preference and reduced immobility time. It reduced serum corticotropin-releasing hormone, adrenocorticotropic hormone, and corticosterone. Additionally, RBS downregulated the expression of glucocorticoid receptor and FK506 binding protein 5 and upregulated the ERK-CREB-BDNF pathway in the prefrontal cortex and hippocampus. Furthermore, RBS increased serotonin, dopamine, and norepinephrine levels and decreased monoamine oxidase mRNA and protein levels in the brain. Thus, RBS administration could be a promising therapeutic approach to treating chronic stress-induced depression.

rice bran

γ-oryzanol

depression

chronic stress

mechanism

Different types of mental disorders can exert diverse effects on cognitive functions, emotional states, and the overall physical health of affected individuals. Depression is emerging as a social and health-related issue in many countries, especially in South Korea, which was reported to be the country with the highest suicide rate in 2021¹. The lifetime prevalence rates of major depressive disorder in the South Korean population increased from 5.6% in 2006 to 7.7% in 2020², and mounting evidence suggests that the coronavirus disease 2019 pandemic has exacerbated the population burden of depression^3,4. Moreover, although there are several treatments for depression, including antidepressant drug therapy, they often have significant limitations in terms of efficacy and side effects. Therefore, there is a need to develop alternative and more efficient therapeutic options.

Although the pathophysiology of depression remains unclear, several hypothetical frameworks have been suggested⁵. Hypothalamic-pituitary-adrenal (HPA) axis dysregulation has been postulated as a contributing factor in the depressive disorders and the underlying mechanisms of antidepressant efficacy⁶. Furthermore, depression has been observed to elicit dysfunction of hippocampal glucocorticoid receptors (GRs), which hold a critical role in providing feedback regulation to the HPA axis⁷. Monoaminergic pathways, which integrate the effects of neurotransmitters such as serotonin, dopamine, and norepinephrine, have been implicated in the development and progression of depression as well⁸. Altered levels or imbalances in these neurotransmitters can influence HPA axis activity⁹. There is also considerable evidence for a key role of extracellular signal-regulated kinase (ERK), cAMP-response element binding protein (CREB), and brain-derived neurotrophic factor (BDNF) in the mechanisms of action of antidepressants. The ERK-CREB-BDNF signaling pathway regulates the gene expressions that promote synaptic and neural plasticity¹⁰; therefore, dysfunctions in this signaling network can disrupt neuroplasticity and compromise neuronal function, thereby contributing to the development of depression. Collectively, these observations indicate that the HPA axis, GRs, as well as the monoaminergic and ERK-CREB-BDNF pathways may represent crucial targets of antidepressant actions.

In recent years, the utilization of natural medicines and remedies as potential treatments for depression has gained considerable interest owing to their effective antidepressant effects and high margins of safety. Rice bran, the residue obtained during rice milling, is a rich source of proteins, fats, vitamins, and phytochemicals (mainly oryzanol, tocopherols, and sterols). Numerous studies have demonstrated the beneficial effects of rice bran, including antidiabetic, antioxidant, anti-inflammatory, lipid-lowering, and neurological properties^11–13. We have previously reported that the administration of rice bran supplement led to a reduction in sleep latency and induced non-rapid eye movement sleep by inhibiting the histamine H₁ receptor in mice, and sleep-promoting effects have been confirmed in humans as well^14–16. It has been reported that γ-oryzanol (ORY) exhibits antidepressant effects in a depression model induced by chronic unpredictable mild stress in Drosophila melanogaster¹⁷. Nevertheless, the investigation in this are remains limited.

Therefore, the aim of this study was to investigate whether rice bran supplement (RBS) would have antidepressant effects in a mouse model of chronic stress-induced depression and to examine the molecular mechanisms underlying the observed effects of RBS. Additionally, the biochemical test for the levels of monoamine neurotransmitters associated with the monoamine system and HPA axis in the brain were studied. We also investigated the ERK-CREB-BDNF pathway in the prefrontal cortex and hippocampus. This study could serve as a reference for the use of RBS in the treatment of depression.

2.1. RBS attenuated depressive-like behaviors induced by chronic restraint stress (CRS)

To examine the antidepressant effects of RBS on mice exposed to repeated CRS, mice were restrained for 6 h per day and administered vehicle (VEH), RBS (250, 500, or 1000 mg/kg body weight [BW]), or the antidepressant imipramine (IMI; 50 mg/kg BW) for 5 weeks. After 5 weeks, behavioral tests were conducted (Fig. 1a). In the CRS + VEH group, BW was significantly lower compared to the non-stressed control (NOR) group. Conversely, RBS administration conferred significant protective effects against CRS-associated weight loss.

The sucrose preference test (SPT) results showed that RBS administration significantly increased sucrose preference, similar to the effects observed with IMI administration as a positive control, in mice subjected to CRS (Fig. 1c). In the tail suspension test (TST), administration of RBS at dosages of 500 and 1,000 mg/kg BW resulted in a significant reduction in immobility time compared to the CRS + VEH group (p < 0.001, Fig. 1d). The effect in the RBS 1,000 mg/kg BW group not significantly different from that of IMI, which significantly reduced the immobility time by 1.94-fold. Similar results were observed in the FST, in which CRS challenge significantly increased the immobility time compared to that in the NOR group, and administration of both RBS and IMI reduced the immobility time (p < 0.001, Fig. 1e). These behavioral test results revealed that RBS administration effectively alleviated depressive-like behaviors in mice subjected to CRS.

2.2. RBS ameliorated CRS-induced HPA axis hyperactivity in mice

Prolonged exposure to chronic stress has been identified as a significant contributing factor to HPA axis dysfunction in depression¹⁸. To explore the impact of RBS on the regulation of the HPA axis, levels of serum corticotropin-releasing hormone (CRH), adrenocorticotropic hormone (ACTH), and corticosterone (CORT) levels were quantified. As shown in Fig. 2b–d, serum CRH, ACTH, and CORT levels in mice subjected to CRS were higher than those in the NOR group; however, these alterations improved in mice treated with 250–1,000 mg/kg BW RBS. Similar effects were observed in the IMI positive control group.

Next, we assessed GR and FK506 binding protein 5 (FKBP5) expression in the prefrontal cortex and hippocampus of mice subjected to CRS. Our results revealed that there was a significant increase in both GR mRNA and protein levels in the CRS + VEH group compared to the NOR group. However, RBS administration downregulated this CRS-induced increase in GR mRNA and protein levels (Fig. 2e). Additionally, the mRNA and protein levels of FKBP5, a known negative regulator of the GR, were significantly elevated in the prefrontal cortex and hippocampus of CRS + VEH group; however, this elevation was also reversed by RBS administration (Fig. 2e). Finally, the results of immunochemistry analysis of in HT22 neuronal cell showed that the CORT-induced translocation of GR from the cytosol to the nucleus was suppressed by RBS treatment (Supplementary Fig. 1).

2.3. RBS restored CRS-induced abnormal alterations in neurotransmitter levels by regulating monoamine oxidase (MAO) activity in mice

Many studies have reported that chronic stress-induced depression is associated with dysregulation of monoaminergic pathways, and the reduction in neurotransmitter levels is considered to be a significant factor in stress-induced depression¹⁹. Therefore, we assessed the effects of RBS on the levels of the neurotransmitters serotonin, dopamine, and norepinephrine in the brain. As shown in Fig. 3b, there were significant reductions in monoamine concentrations in the CRS + VEH group when compared to the NOR group (serotonin: 84.0% reduction, p < 0.01; dopamine: 62.4% reduction, p < 0.05; norepinephrine: 37.2% reduction, p < 0.05). As expected, RBS administration increased the levels of these neurotransmitters in the CRS + RBS 1000 mg/kg BW group (serotonin: 493.3%, p < 0.05; dopamie: 234.5%, p < 0.05; noreinephrine: 167.1%, p < 0.05), which was similar to the observation in the CRS + IMI group.

MAO is an enzyme that catalyzes the degradation of monoamines. It plays a critical role in regulating monoamine levels in the brain and has been implicated in depression and other neuropsychiatric disorders. Therefore, we measured MAO mRNA and protein levels in the prefrontal cortex and hippocampus of mice with CRS-induced depression. As shown in Fig. 3c–f, the protein and mRNA levels of MAO-A and MAO-B in both the prefrontal cortex and hippocampus were elevated in the CRS + VEH group compared to the NOR group, whereas these changes was attenuated in RBS-treated mice.

2.4. RBS activated the ERK-CREB-BDNF signaling pathway in the prefrontal cortex and hippocampus of CRS-exposed mice

To explore the potential antidepressant effects of RBS, western blotting was performed to analyze several key components of the ERK-CREB-BDNF signaling pathway in the prefrontal cortex and hippocampus. As shown in Fig. 4, the results indicate that ERK and CREB phosphorylation and BDNF levels in the prefrontal cortex and hippocampus were lower in the CRS + VEH group than those in the NOR group. However, these values were increased following RBS treatment.

2.5. ORY, a major component of RBS, attenuated CRS-induced depressive-like behaviors

ORY, stigmasterol, β-sitosterol, and α-tocopherol are the representative bioactive components of rice bran²⁰. Ultraperformance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) analysis confirmed that the presence of all four of these in the RBS used in this study (Fig. 5; approximate concentrations: ORY, 5.64 mg; β-sitosterol, 2.57 mg; stigmasterol, 0.56 mg; α-tocopherol, 0.18 mg per g of RBS). As the ORY content was much higher than that of the other major components, we investigated the effects of ORY on the CRS-induced depression animal model (Fig. 6a). ORY significantly increased sucrose preference compared to that in the CRS + VEH group (Fig. 6c). Furthermore, ORY administration resulted in a significant decrease in immobility time in both the TST and FST (Fig. 6d and e).

The present study sought to investigate the antidepressant effects of RBS on mice subjected to CRS and to examine the associate signaling pathways in the prefrontal cortex and hippocampus. Our findings demonstrate that RBS effectively alleviated depressive-like behaviors in CRS-exposed mice and significantly improved the markers of depression associated with the HPA axis, neurotransmitter levels, and ERK-CREB-BDNF signaling in the prefrontal cortex and hippocampus.

Chronic stress has been widely used to induce depressive behaviors in rodents to model the environmental risk factors that influence humans. Numerous studies have utilized chronic stress paradigms, such as CRS, social defeat stress, and chronic unpredictable mild stress, to induce depression in rodent models^21–23. CRS is a well-validated and commonly used method of inducing depressive behavior in rodents²⁴. CRS procedures induce changes in BW, behaviors, hormone, and monoamine neurotransmitter levels²⁵. Consistent with these findings, our results observed that mice exposed to CRS exhibited depressive-like behaviors, as indicated by reduced BW, decreased sucrose preference, and increased immobility time in both the TST and FST. Moreover, RBS effectively ameliorated the CRS-induced depression-like phenotypes, similar to the effects of the antidepressant drug, IMI. These findings suggest that potential of RBS as a promising candidate for further development as an antidepressant agent.

The HPA axis is crucial neuroendocrine pathway that modulates various stress responses, emotions, and immune system-related functions. In response to stress, the HPA axis is activated, leading to the synthesis and release of glucocorticoids²⁶. GR, which is activated by glucocorticoids, can translocate into the nucleus and bind to glucocorticoid response elements to initiate a stress response to cope with the stressors^27,28. However, chronic stress disrupts the normal regulation of the HPA axis, leading to persistently elevated glucocorticoid levels. Moreover, an abnormal increase in glucocorticoid levels leads to GR resistance, which is characterized by reduced nuclear translocation of the GR and contributes to dysregulation of the stress response system²⁹. FKBP5, a co-chaperone of heat shock protein 90, plays an important role in modulating the sensitivity of GRs and the HPA axis³⁰. It is also involved in significant gene-environment interactions that contribute to the development of stress-related mental disorders²⁹. Furthermore, chronic stress has been reported to alter FKBP5 expression³¹, and increased FKBP5 expression inhibits GR translocation into the nucleus, thereby impairing GR sensitivity. In the present study, RBS administration inhibited the CRS-induced increase in serum CRH, ACTH, and CORT levels. RBS also downregulated the protein and mRNA levels of GR and FKBP5 in the prefrontal cortex and hippocampus of CRS-exposed mice. Additionally, RBS resulted in a reduction of GR nuclear translocation in HT22 cells, indicating impaired GR-dependent transcriptional regulation of target genes. Collectively, our results suggest that RBS might recover HPA axis dysfunction induced by chronic stress. Consistent with our findings, larger changes in the ventral hippocampus and prefrontal cortex have been reported following chronic mild stress, and these alterations were modulated by duloxetine treatment³¹. Therefore, our results suggest that RBS administration attenuates CRS-induced GR and FKBP5 expression, which may have contributed to the amelioration of HPA axis hyperactivity in depressive model mice.

Monoamines play crucial roles as neuromodulators in the development of emotional disorders³². MAO, which exists in two isoforms, MAO-A and MAO-B, functions to degrade monoamine neurotransmitters. Several studies have consistently shown that CRS leads to MAO activation and the subsequent reduction of monoamine neurotransmitter levels. Dysregulation of the monoaminergic systems in the brain has been implicated in various emotional disorders^33,34. Consequently, numerous antidepressant medications have been developed to specifically target and inhibit MAO with the aim of restoring the balance of monoamine levels and alleviating depressive symptoms. In our study, we observed that a significant increase in the levels of the neurotransmitters serotonin, dopamine, and norepinephrine in the brains of CRS-induced mice following the administration of RBS. Additionally, RBS reversed the increase in the mRNA and protein levels of both MAO-A and MAO-B in the prefrontal cortex and hippocampus of CRS-induced mice. These inhibitory effects on MAO were associated with concurrent alterations in monoamine neurotransmitter levels. Therefore, these findings suggest that the antidepressant-like effects of RBS may be attributed to its ability to regulate abnormal variations in neurotransmitter levels and MAO expression in the brain, leading to the normalization of monoaminergic systems.

ERK phosphorylation has been recognized as a crucial intracellular signaling mechanism in the antidepressant efficacy observed in both individuals with depression and various animal models of depression. CREB plays a crucial role in both neuroplasticity and neurogenesis. Additionally, it regulates the transcription of various depression-related proteins, such as BDNF, and neuropeptides upon phosphorylation³⁵. BDNF, a member of the neurotrophin family, plays critical roles in cognitive function and mood regulation³⁶. Various stress-related procedures have been shown to reduce BDNF levels in the prefrontal cortex and hippocampus, whereas treatment with antidepressants has been found to increase BDNF levels in these regions³⁷. Therefore, the ERK-CREB-BDNF signaling pathway may be critical to understanding the pathogenesis of depression. In our study, we found a significant decrease in the levels of BDNF and phosphorylated ERK and CREB in the prefrontal cortex and hippocampus of CRS-exposed mice. However, treatment with RBS effectively reversed these changes. Thus, these observations indicate that RBS activates ERK-CREB-BDNF signaling pathways, potentially contributing to the alleviation of depressive-like behavior in CRS-exposed mice.

UPLC-MS/MS analysis detected all four major rice bran components (ORY, stigmasterol, β-sitosterol, and α-tocopherol) in the RBS used in this study. Of them, the concentration of ORY was the highest. ORY is a widely recognized bioactive component found in rice bran, known for its reported antidepressant-like effects. Araujo et al. reported that it had antidepressant-like effects in Drosophila melanogaster exposed to chronic unpredictable mild stress¹⁷. Additionally, Akter et al. demonstrated that ORY exhibits anxiolytic effects by ameliorating acute stress-induced behavioral anxiety in mice and attenuates alcohol-induced anxiety via the upregulation of monoamines, BDNF, and IL-1β signaling^38,39. These findings are in line with our results, indicating that ORY treatment effectively alleviated depressive-like behaviors in mice exposed to CRS. Our results suggest that ORY might be the key active compound contributing to the antidepressant effects of RBS on CRS-induced mice.

However, our study has certain limitations in our study need to be acknowledged. First, evaluating the antidepressant efficacy of ORY in a variety of depressive animal, such as social defeat stress, would be valuable to establish its broader therapeutic potential. Second, although ORY can cross the blood-brain barrier, further research is needed to understand the impact of metabolites on depression. Lastly, clinical trials are required to validate the potential of RBS as an alternative treatment for depression.

In conclusion, our study demonstrated that RBS exerts antidepressant-like effects in mice with CRS-induced depression. The beneficial effects of RBS may be attributed to its ability to normalize HPA axis hyperactivity, maintain monoamine levels by reducing MAO expression, and regulate the ERK-CREB-BDNF signaling pathways. Our study highlights the potential of RBS as a promising adjunct treatment for depression.

4.1. Chemicals and reagents

A CRH ELISA kit was acquired from MyBioSource (San Diego, CA, USA). The ACTH ELISA kit was obtained from LS Bio (Seattle, WA, USA). The CORT ELISA kit was purchased from Enzo Life Sciences (Farmingdale, NY, USA). ELISA kits for serotonin and dopamine were purchased from Abcam (Cambridge, UK). The norepinephrine ELISA kit was obtained from Feiyue Bio (Beijing, China). Radioimmunoprecipitation assay (RIPA) buffer containing a protease and phosphatase inhibitor cocktail was purchased from Sigma-Aldrich (St. Louis, MO, USA). The BCA protein kit was purchased from Thermo Fisher Scientific. Tris-buffered saline (TBS) and a chemiluminescent western blotting detection kit were procured from Santa Cruz Biotechnology (Dallas, TX, USA). The Nucleospin® RNA XS kit was purchased from Macherey-Nagel (Düren, Germany). The ReverTra Ace qPCR RT Master Mix kit was obtained from TOYOBO (Osaka, Japan), and the SYBR Green Real-time PCR Master Mix was obtained from Takara (Kyoto, Japan).

4.2. Preparation of RBS

Rice bran (Lot No. 220114-002) was supplied by S&D (Cheongju, Korea). Briefly, rice bran was subjected to extraction in 20% ethanol solution (10 times) at 40°C for 8 h. Thereafter, the extract was vacuum concentrated and spray-dried to obtain the powdered RBS.

4.3. Animals

All animal procedures were conducted in accordance with the guidelines and regulations of the Institutional Animal Care and Use Committee of Korea Food Research Institute (permission number: KFRI-M-16062). Additionally, all experiments were performed adhering to the ARRIVE guidelines 2.0. Male ICR mice (4-week old, 19–23 g) were obtained from Koatech Co., Ltd. (Pyeongtaek, Korea) and allowed to acclimate in their cages for one week before being used in the experiments. All mice were housed in controlled conditions (temperature: 23 ± 1°C, humidity: 55 ± 5%) and light-dark cycle (lights on from 07:00 to 19:00, light intensity: 3000 lux) and had ad libitum access to standard feed and water. RBS (250, 500, and 1000 mg/kg BW), ORY (50, 100, and 200 mg/kg BW), and IMI (50 mg/kg BW) in saline solution with 5% Tween 80 were orally administered to the mice every day for 5 weeks, 1 h before the experimental procedures⁴⁰. The RBS and ORY doses were selected with reference to previous studies^14,41.

In this study, the mouse model of stress-induced depression was established using chronic restraint stress (CRS) as the stressor. A custom-made 50 mL conical tube with multiple holes on the top, sides, and cap was used to restrain the mice. The mice were subjected to prolonged restraint stress for a duration of 6 h per day for 5 weeks^42,43. The experimental animals were acclimated to the behavioral testing room for 1 h prior to the experiments.

4.4. Behavioral tests

4.4.1. SPT

SPT was performed using the method described by Luo et al.⁴⁴ Two days before the experiment, one of the water bottles was replaced with regular water, and food and water deprivation was carried out the day before the experiment. On the day of the experiment, 100 ml of 1% sucrose solution and regular water were provided in two water bottles. After 3 h, the bottle weights were measured to calculate the sucrose preference.

4.4.2. TST

The TST was performed as described by Steru et al.⁴⁵ The immobility time was recorded for a duration of 6 min using an immobility measurement device (ID-Tech Bioseb, Chaville, France).

4.4.3. FST

The FST was performed as described by Castagne et al.⁴⁶ The immobility time was analyzed during the last 4 min of the test, excluding the initial 2 min. The recorded videos were analyzed using a video tracking software (Smart 3.0, Panlab, Spain).

4.5. Measurement of serum CRH, ACTH, and CORT levels

Serum levels of CRH, ACTH, and CORT levels were quantified using their respective ELISA kits, following the manufacturer’s instructions. The optical density (OD) of the samples at 450 nm was measured using a microplate reader (Molecular Devices, Sunnyvale, CA, USA).

4.6 Measurement of brain monoamine levels

Serotonin, dopamine, and norepinephrine levels in the brain were quantified following the manufacturer’s instructions. The OD of the samples at 450 nm was measured using a microplate reader.

4.7. Immunoblotting

Prefrontal cortex and hippocampal brain tissues were homogenized using RIPA buffer with a protease and phosphatase inhibitor cocktail. The quantified proteins were separated using 10% SDS-PAGE and then transferred to PVDF membranes. Next, the membranes were blocked with skim milk for 1 h and incubated overnight at 4°C with the relevant primary antibodies. Following three 10 min washed with TBST, the membranes were incubated with secondary antibodies for 2 h at room temperature. After additional washing, the membranes were visualized using a chemiluminescence imaging system (Vilber Lourmat, France). Relative protein densities were quantified using ImageJ (National Institutes of Health, Bethesda, MD, USA).

4.8. Real-time PCR

RT-qPCR was performed as described by Lim et al⁴⁷. The primer sequences used were as follows: mouse GR, forward: 5′-AGGCCGCTCAGTGTTTTCTA-3′ and reverse: 5′-TACAGCTTCCACACGTCAGC-3′; FKBP5, forward: 5′-CGGCGACAGGTCTTCTACTT-3′ and reverse: 5′-TCTTCACCCTGCTCAGTCAT-3′; MAO-A, forward: 5′-GGTCCTCCTTGGGGATAAAG-3′ and reverse: 5′-TTCTCTCAGGTGGAAGCTCTG-3′; MAO-B, forward: 5′-ATGAGCAACAAAAGCGATGTGA-3′ and reverse: 5′-TCCTAATTGTGTAAGTCCTGCCT-3′; β-actin, forward: 5′-CGAGCACAGCTTCTTTGCAGC-3′ and reverse: 5′-CCTTCTGACCCATTCCCACC-3′. To normalize the expression of target genes, the housekeeping gene β-actin was employed. The data were analyzed using the ΔΔCt method.

4.9. UPLC-MS/MS analysis

Samples were analyzed using a micro mass spectrometer (Waters Xevo TQ-S; Milford, MA, USA) and a Waters ACQUITY UPLC C8 column (2.1 × 100 mm, 1.7 mm) interfaced with atmospheric pressure chemical ionization. The flow rate was set at 0.5 mL/min, and the capillary temperature was set at 35°C. Gradient elution was performed using 0.1% formic acid in distilled water (solvent A) and 0.1% formic acid in acetonitrile (solvent B). A 10 min linear gradient of 100% B followed by a 2 min linear gradient of 100% B was used for chromatographic separation. The gradient was followed by a 3 min wash with 5% B and a 5-min equilibration with 5% B. The injection volume was set to 5 µL, and the total run time was of the chromatographic analysis was 20 min. The mass spectrometer operated in the positive electrospray mode, with the following source parameters: capillary voltage, 3.0 kV; source temperature, 150°C; and desolvation flow, 250 L/h. LC and MS analyses were conducted using the MassLynx software (Waters, Milford, MA, USA version 4.1). The mass transition, collision energy, and cone voltage were m/z 359.09 → 146.87, 25 eV, and 20 V for stigmasterol; m/z 397.10 → 146.94, 25 eV, and 20 V for β-sitosterol; m/z 430.13 → 164.95, 30 eV, and 16 V for α -tocopherol; and m/z 603.17 → 409.05, 10 eV, and 20 V for ORY, respectively.

4.10. Statistical analysis

All experimental data are expressed as the mean ± standard error of the mean values. Statistical differences were assessed using one-way analysis of variance (ANOVA), followed by Tukey’s post-hoc test. GraphPad Prism 8 (GraphPad Software, Inc., San Diego, CA, USA) was utilized for all statistical analyses. A significance level of p < 0.05 was considered as the threshold for statistical significance.

ACTH, adrenocorticotropic hormone; ANOVA, analysis of variance; BDNF, brain-derived neurotrophic factor; CORT, corticosterone; CREB, cAMP-response element binding protein; CRH, corticotropin-releasing hormone; CRS, chronic restraint stress; ERK, extracellular signal-regulated kinase; FST, forced swimming test; GR, glucocorticoid receptor; HPA axis, hypothalamic-pituitary-adrenal axis; IMI, imipramine; MAO, monoamine oxidase; OFT, open field test; ORY, γ-oryzanol; RBS, rice bran supplement.; RT, room temperature; SPT, sucrose preference test; TBS, Tris-buffered saline; TST, tail suspension test

Data availability

The datasets used and/or analyzed during the current study are available from the corresponding author on reasonable request.

Acknowledgments

This study was supported by the Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries (IPET) through the High Value-Added Food Technology Development Program funded by the Ministry of Agriculture, Food and Rural Affairs (MAFRA) [grant number 116036-03] and by the Main Research Program of the Korea Food Research Institute funded by the Ministry of Science and ICT [grant number E0210201].

Author contributions

MYU and SC contributed to the study design. MK and MY performed the experiments and analyzed the data. MK and MYU wrote and edited the manuscript. SC reviewed the manuscript. All authors read and approved the final manuscript.

Competing interests

The authors declare no competing interests.

World Health Organization https://www.who.int/news-room/fact-sheets/detail/depression (2021).
Kim, M. Ministry of Health and Welfare https://www.mohw.go.kr/react/al/sal0301vw.jsp?PAR_MENU_ID=04&MENU_ID=0403&page=1&CONT_SEQ=369088 (2021).
Cho, S., Ju, H. R., Oh, H., Choi, E.-S. & Lee, J. A. The association between the restriction of daily life and depression during the COVID-19 pandemic in Korea: a nationwide based survey. Scientific Reports 12, 17722 (2022).
Hyun, J. et al. COVID-19 and risk factors of anxiety and depression in South Korea. Psychiatry Investigation 18, 801 (2021).
Ménard, C., Hodes, G. E. & Russo, S. J. Pathogenesis of depression: insights from human and rodent studies. Neuroscience 321, 138-162 (2016).
Kunugi, H., Hori, H., Adachi, N. & Numakawa, T. Interface between hypothalamic‐pituitary‐adrenal axis and brain‐derived neurotrophic factor in depression. Psychiatry and clinical neurosciences 64, 447-459 (2010).
Mizoguchi, K., Ishige, A., Aburada, M. & Tabira, T. Chronic stress attenuates glucocorticoid negative feedback: involvement of the prefrontal cortex and hippocampus. Neuroscience 119, 887-897 (2003).
Delgado, P. L. Depression: the case for a monoamine deficiency. Journal of clinical Psychiatry 61, 7-11 (2000).
Smith, S. M. & Vale, W. W. The role of the hypothalamic-pituitary-adrenal axis in neuroendocrine responses to stress. Dialogues in clinical neuroscience (2022).
Ying, S.-W. et al. Brain-derived neurotrophic factor induces long-term potentiation in intact adult hippocampus: requirement for ERK activation coupled to CREB and upregulation of Arc synthesis. Journal of Neuroscience 22, 1532-1540 (2002).
Kahlon, T. S., Chow, F. I., Sayre, R. N. & Betschart, A. A. Cholesterol-lowering in hamsters fed rice bran at various levels, defatted rice bran and rice bran oil. The Journal of nutrition 122, 513-519 (1992).
Rhee, Y.-H., Rhee, C. H., Chung, P.-S. & Ahn, J.-C. Anti-oxidant and anti-inflammatory effects of rice bran and green tea fermentation mixture on lipopolysaccharideinduced RAW 264.7 macrophages. Tropical Journal of Pharmaceutical Research 16, 2943-2951 (2017).
Lim, D. W. et al. Standardized rice bran extract improves hepatic steatosis in HepG2 cells and ovariectomized rats. Nutrition Research and Practice 14, 568-579 (2020).
Um, M. Y. et al. A novel neurological function of rice bran: a standardized rice bran supplement promotes non‐rapid eye movement sleep in mice through histamine H1 receptors. Molecular nutrition & food research 61, 1700316 (2017).
Um, M. Y. et al. Rice bran extract supplement improves sleep efficiency and sleep onset in adults with sleep disturbance: a randomized, double-blind, placebo-controlled, polysomnographic study. Scientific Reports 9, 12339 (2019).
Ross, R. A., Foster, S. L. & Ionescu, D. F. The role of chronic stress in anxious depression. Chronic Stress 1, 2470547016689472 (2017).
Araujo, S. M. et al. γ-Oryzanol produces an antidepressant-like effect in a chronic unpredictable mild stress model of depression in Drosophila melanogaster. Stress 24, 282-293 (2021).
Mikulska, J., Juszczyk, G., Gawrońska-Grzywacz, M. & Herbet, M. HPA axis in the pathomechanism of depression and schizophrenia: new therapeutic strategies based on its participation. Brain Sciences 11, 1298 (2021).
Tafet, G. E. & Nemeroff, C. B. The links between stress and depression: psychoneuroendocrinological, genetic, and environmental interactions. The Journal of neuropsychiatry and clinical neurosciences 28, 77-88 (2016).
Sharif, M. K., Butt, M. S., Anjum, F. M. & Khan, S. H. Rice bran: A novel functional ingredient. Critical reviews in food science and nutrition 54, 807-816 (2014).
Oh, D.-R. et al. Vaccinium bracteatum leaf extract reverses chronic restraint stress-induced depression-like behavior in mice: regulation of hypothalamic-pituitary-adrenal axis, serotonin turnover systems, and ERK/Akt phosphorylation. Frontiers in Pharmacology 9, 604 (2018).
Gáll, Z. et al. Effects of chronic cannabidiol treatment in the rat chronic unpredictable mild stress model of depression. Biomolecules 10, 801 (2020).
Yoshida, K. et al. Chronic social defeat stress impairs goal-directed behavior through dysregulation of ventral hippocampal activity in male mice. Neuropsychopharmacology 46, 1606-1616 (2021).
Tan, S., Wang, Y., Chen, K., Long, Z. & Zou, J. Ketamine alleviates depressive-like behaviors via down-regulating inflammatory cytokines induced by chronic restraint stress in mice. Biological and Pharmaceutical Bulletin 40, 1260-1267 (2017).
Mahar, I., Bambico, F. R., Mechawar, N. & Nobrega, J. N. Stress, serotonin, and hippocampal neurogenesis in relation to depression and antidepressant effects. Neuroscience & Biobehavioral Reviews 38, 173-192 (2014).
Zhang, K. et al. Revealing antidepressant mechanisms of baicalin in hypothalamus through systems approaches in corticosterone-induced depressed mice. Frontiers in neuroscience 13, 834 (2019).
Binder, E. B. The role of FKBP5, a co-chaperone of the glucocorticoid receptor in the pathogenesis and therapy of affective and anxiety disorders. Psychoneuroendocrinology 34, S186-S195 (2009).
Djordjevic, A., Adzic, M., Djordjevic, J. & Radojcic, M. B. Stress type dependence of expression and cytoplasmic-nuclear partitioning of glucocorticoid receptor, hsp90 and hsp70 in Wistar rat brain. Neuropsychobiology 59, 213-221 (2009).
Matosin, N., Halldorsdottir, T. & Binder, E. B. Understanding the molecular mechanisms underpinning gene by environment interactions in psychiatric disorders: the FKBP5 model. Biological psychiatry 83, 821-830 (2018).
Li, H. et al. The glucocorticoid receptor–FKBP51 complex contributes to fear conditioning and posttraumatic stress disorder. The Journal of clinical investigation 130, 877-889 (2020).
Guidotti, G. et al. Glucocorticoid receptor and FKBP5 expression is altered following exposure to chronic stress: modulation by antidepressant treatment. Neuropsychopharmacology 38, 616-627 (2013).
Zhang, L.-L. et al. Antidepressant-like effect of Citrus sinensis (L.) Osbeck essential oil and its main component limonene on mice. Journal of agricultural and food chemistry 67, 13817-13828 (2019).
Youdim, M. B., Edmondson, D. & Tipton, K. F. The therapeutic potential of monoamine oxidase inhibitors. Nature reviews neuroscience 7, 295-309 (2006).
Duncan, J., Johnson, S. & Ou, X.-M. Monoamine oxidases in major depressive disorder and alcoholism. Drug discoveries & therapeutics 6, 112-122 (2012).
Yao, W. et al. Microglial ERK-NRBP1-CREB-BDNF signaling in sustained antidepressant actions of (R)-ketamine. Molecular psychiatry 27, 1618-1629 (2022).
Teixeira, A. L., Barbosa, I. G., Diniz, B. S. & Kummer, A. Circulating levels of brain-derived neurotrophic factor: correlation with mood, cognition and motor function. Biomarkers in medicine 4, 871-887 (2010).
Jiang, B. et al. Antidepressant‐like effects of ginsenoside Rg1 are due to activation of the BDNF signalling pathway and neurogenesis in the hippocampus. British journal of pharmacology 166, 1872-1887 (2012).
Akter, S., Sasaki, H., Ikeda, Y., Miyakawa, H. & Shibata, S. γ-oryzanol ameliorates the acute stress induced by behavioral anxiety testing in mice. Journal of Pharmacological Sciences 138, 155-159 (2018).
Akter, S., Uddin, K. R., Sasaki, H., Lyu, Y. & Shibata, S. Gamma oryzanol impairs alcohol-induced anxiety-like behavior in mice via upregulation of central monoamines associated with Bdnf and Il-1β signaling. Scientific reports 10, 10677 (2020).
Yi, J. H. et al. Rubrofusarin attenuates chronic restraint stress-induced depressive symptoms. International Journal of Molecular Sciences 21, 3454 (2020).
Kobayashi, E. et al. Evaluation of γ-oryzanol accumulation and lipid metabolism in the body of mice following long-term administration of γ-oryzanol. Nutrients 11, 104 (2019).
Ha, G. E. & Cheong, E. Chronic Restraint Stress Decreases the Excitability of Hypothalamic POMC Neuron and Increases Food Intake. Experimental Neurobiology 30, 375 (2021).
Wang, H. et al. Ginsenoside Re protects against chronic restraint stress‐induced cognitive deficits through regulation of NLRP3 and Nrf2 pathways in mice. Phytotherapy Research 35, 2523-2535 (2021).
Luo, D., An, S. & Zhang, X. Involvement of hippocampal serotonin and neuropeptide Y in depression induced by chronic unpredicted mild stress. Brain research bulletin 77, 8-12 (2008).
Steru, L., Chermat, R., Thierry, B. & Simon, P. The tail suspension test: a new method for screening antidepressants in mice. Psychopharmacology 85, 367-370 (1985).
Castagné, V., Moser, P., Roux, S. & Porsolt, R. D. Rodent models of depression: forced swim and tail suspension behavioral despair tests in rats and mice. Curr. Protoc. Neurosci. 55, 8.10 A. 11-18.10 A. 14 (2011).
Lim, D. W. et al. 1, 3-Dicaffeoylquinic acid as an active compound of Arctium lappa root extract ameliorates depressive-like behavior by regulating hippocampal nitric oxide synthesis in ovariectomized mice. Antioxidants 10, 1281 (2021).

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A novel properties of rice bran: rice bran supplement alleviates chronic restraint stress-induced depression-like behaviors in mice

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Abstract

Figures

1. Introduction

2. Results

2.1. RBS attenuated depressive-like behaviors induced by chronic restraint stress (CRS)

2.2. RBS ameliorated CRS-induced HPA axis hyperactivity in mice

2.4. RBS activated the ERK-CREB-BDNF signaling pathway in the prefrontal cortex and hippocampus of CRS-exposed mice

2.5. ORY, a major component of RBS, attenuated CRS-induced depressive-like behaviors

3. Discussion

4. Methods

4.1. Chemicals and reagents

4.2. Preparation of RBS

4.3. Animals

4.4. Behavioral tests

4.4.1. SPT

4.4.2. TST

4.4.3. FST

4.5. Measurement of serum CRH, ACTH, and CORT levels

4.6 Measurement of brain monoamine levels

4.7. Immunoblotting

4.8. Real-time PCR

4.9. UPLC-MS/MS analysis

4.10. Statistical analysis

Abbreviations

Declarations

References

Additional Declarations

Supplementary Files

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