Background In these days, the occurrence of neuropsychological complications during perioperative period has become the subject of discussion. Diabetes is indicated as one of the metabolic risk factors. Although the number of patients with diabetes mellitus (DM) has been increasing, the pathophysiology of postoperative neuropsychological dysfunction in DM patient is still unclear. Recently, a deficiency of neurotransmitters, such as monoamines, was reported to be associated with mental disorders. Therefore, we investigated the effects of surgical stress on behavioral activity and the hippocampal noradrenaline (NA) level in type 2 diabetes mellitus model (T2DM) mice.Methods Eighty-four 6-week-old male C57BL/6J mice were divided into four groups (control, surgery control, T2DM, and surgery T2DM groups). T2DM mice were established by feeding a high fat diet (HFD) for 8 weeks. At 14 weeks of age, fifteen mice in every group underwent a series of behavioral tests including an open field (OF) test, a novel objective recognition (NOR) test and a light-dark box (LD) test. In the surgery groups, open abdominal surgery with manipulation of intestine was performed 24 hours before the behavioral tests as a surgical stress. Hippocampal NA level was examined in six mice in each group by high-performance liquid chromatography. The data were analyzed by Mann-Whitney U test and P values less than 0.05 were considered significant.Results The T2DM group showed significantly increased explorative activity in the NOR test (P = 0.0016) and significantly increased transition in the LD test (P = 0.043) compared with those in the control group before surgery. In T2DM mice, surgical stress resulted in decreased total distance in the OF test, decreased explorative activity in the NOR test, and decreased transition in the LD test (OF: P = 0.015, NOR: P = 0.009, LD: P = 0.007) and decreased hippocampal NA (P = 0.015), although they were not revealed in control mice.Conclusion T2DM mice by feeding a HFD showed increased behavioral activities, and surgical stress in T2DM mice caused postoperative hypoactivity and reduction of hippocampal NA level.

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On 10 Feb, 2020
On 09 Feb, 2020
On 08 Feb, 2020
On 08 Feb, 2020
On 30 Jan, 2020
Received 29 Jan, 2020
Received 28 Jan, 2020
On 13 Jan, 2020
On 12 Jan, 2020
Invitations sent on 08 Jan, 2020
On 26 Dec, 2019
On 25 Dec, 2019
On 25 Dec, 2019
Posted 01 Nov, 2019
On 14 Dec, 2019
Received 19 Nov, 2019
On 10 Nov, 2019
Received 08 Nov, 2019
On 06 Nov, 2019
On 06 Nov, 2019
Invitations sent on 03 Nov, 2019
On 28 Oct, 2019
On 18 Oct, 2019
On 17 Oct, 2019
On 17 Oct, 2019
On 10 Feb, 2020
On 09 Feb, 2020
On 08 Feb, 2020
On 08 Feb, 2020
On 30 Jan, 2020
Received 29 Jan, 2020
Received 28 Jan, 2020
On 13 Jan, 2020
On 12 Jan, 2020
Invitations sent on 08 Jan, 2020
On 26 Dec, 2019
On 25 Dec, 2019
On 25 Dec, 2019
Posted 01 Nov, 2019
On 14 Dec, 2019
Received 19 Nov, 2019
On 10 Nov, 2019
Received 08 Nov, 2019
On 06 Nov, 2019
On 06 Nov, 2019
Invitations sent on 03 Nov, 2019
On 28 Oct, 2019
On 18 Oct, 2019
On 17 Oct, 2019
On 17 Oct, 2019
Background In these days, the occurrence of neuropsychological complications during perioperative period has become the subject of discussion. Diabetes is indicated as one of the metabolic risk factors. Although the number of patients with diabetes mellitus (DM) has been increasing, the pathophysiology of postoperative neuropsychological dysfunction in DM patient is still unclear. Recently, a deficiency of neurotransmitters, such as monoamines, was reported to be associated with mental disorders. Therefore, we investigated the effects of surgical stress on behavioral activity and the hippocampal noradrenaline (NA) level in type 2 diabetes mellitus model (T2DM) mice.Methods Eighty-four 6-week-old male C57BL/6J mice were divided into four groups (control, surgery control, T2DM, and surgery T2DM groups). T2DM mice were established by feeding a high fat diet (HFD) for 8 weeks. At 14 weeks of age, fifteen mice in every group underwent a series of behavioral tests including an open field (OF) test, a novel objective recognition (NOR) test and a light-dark box (LD) test. In the surgery groups, open abdominal surgery with manipulation of intestine was performed 24 hours before the behavioral tests as a surgical stress. Hippocampal NA level was examined in six mice in each group by high-performance liquid chromatography. The data were analyzed by Mann-Whitney U test and P values less than 0.05 were considered significant.Results The T2DM group showed significantly increased explorative activity in the NOR test (P = 0.0016) and significantly increased transition in the LD test (P = 0.043) compared with those in the control group before surgery. In T2DM mice, surgical stress resulted in decreased total distance in the OF test, decreased explorative activity in the NOR test, and decreased transition in the LD test (OF: P = 0.015, NOR: P = 0.009, LD: P = 0.007) and decreased hippocampal NA (P = 0.015), although they were not revealed in control mice.Conclusion T2DM mice by feeding a HFD showed increased behavioral activities, and surgical stress in T2DM mice caused postoperative hypoactivity and reduction of hippocampal NA level.

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6
This is a list of supplementary files associated with this preprint. Click to download.
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