Acute pancreatitis, characterized by hyperactivation of enzymes, is initiated by the production of pro-inflammatory mediators. Hyperactivation of enzymes causes acinar cell necrosis and a complex cascade of events (Leema 2018). It is one of the most common gastrointestinal disorders requiring emergency hospitalization worldwide (Working Group IAP/APA Acute Pancreatitis Guidelines 2013, Tigliano 2017). Still, new anti-inflammatory therapeutic agents with fewer side effects are needed to keep acute pancreatitis under control (El-Ashmawy 2018a). The present study aimed to evaluate the possible anti-inflammatory effects of FA, known to have antioxidant and anti-inflammatory properties and is found in various cereals and fruits, on the pathogenesis of acute pancreatitis.
Due to the release of proinflammatory cytokines, the hyperactivation of digestive enzymes such as pancreatic amylase and lipase occurs (El-Ashmawy 2018b). Moreover, increased permeability in the basal poles of acinar cells causes a significant increase in serum enzyme levels (Yadav 2002). Although there is a debate about the specificity and sensitivity of these two enzyme levels, these two enzyme levels are essential for acute pancreatitis diagnosis (Ma 2012). In this study, serum pancreatic amylase and lipase levels were analyzed, and serum enzyme levels were significantly increased at 48 hours after pancreatitis induction in animals compared to the control group. Furthermore, this study showed for the first time that both doses of FA decreased serum pancreatic amylase levels at 48 hours and also that FA treatment decreased serum lipase levels at 24 and 48 hours after pancreatic induction.
In clinics, ALT, AST, ALP, and TB levels are commonly used parameters for the diagnosis of biliary pancreatitis, and it has been reported that there is a correlation between the enzyme levels and pancreatitis severity (van Santvoort 2011, Zarnescu 2015). In our study, serum ALT, AST, ALP, and TB levels of the PBDL group significantly increased compared to the control group at each time point. ALP levels decreased at the 24th hour in rats treated with FA500 mg/kg. Moreover, 500 mg/kg FA treatment reduced the serum ALT and AST levels at the 48th hour. On the other hand, at 250 mg/kg FA treatment, AST levels decreased at the 48th hour. TB levels decreased in both treatment doses significantly at the 72nd hour. This study showed that FA decreased high levels of liver enzymes induced by pancreaticobiliary obstruction. These results support the notion that FA has a healing role in acute pancreatitis. Similar to our results, a hepatotoxicity study reported that ferulic acid treatment significantly decreased serum ALT, AST, and TB levels. (Panneerselvam 2013).
The relationship between increased pancreatic enzyme levels and the accumulation of neutrophils is a crucial factor in the action mechanism of acute pancreatitis. In previous studies, it has been shown that neutrophils lead to the activation of many proenzymes and the secretion of several inflammatory mediators in the pancreatic tissue (Awla 2012). In our study, MPO activity was measured as an indicator of neutrophil infiltration (Leema 2018). MPO activity increased in the saline-treated pancreatitis group compared to the control group, whereas it significantly decreased in two doses of the FA treatment group. The results show that neutrophils have a role in the pathogenesis of pancreatitis and FA treatment has an anti-inflammatory effect on pancreatitis by decreasing MPO activity. In agreement with our results, Bami et al. reported that the treatment with FA decreased tissue MPO activity in the Cisplatin-induced nephrotoxicity model. (Bami 2017).
Oxidative stress occurs in acute pancreatitis and plays a crucial role in local and systemic processes in pancreatitis (Escobar 2012, Que 2010). Furthermore, it has been shown that MDA levels correlate with the severity of acute pancreatitis and multiple organ failure (Shi 2005). In the study, pancreas-bile duct ligation led to high MDA levels, which is a stable end product of lipid peroxidation. On the other hand, treatment with FA diminished MDA levels. A recent study showed that FA treatment decreased MDA levels in spleen damage-induced diabetic rats (Ghosh 2018). Besides MDA levels, GSH is measured in the study. GSH is the first cellular ROS scavenger in acute pancreatitis and is an endogenous antioxidant (Uçmak 2016, Martinez-Useros 2017). Acute pancreatitis damages endogenous protective mechanisms as an indicator of oxidative stress and causes a decrease in GSH levels (Zhu 2008, Letoha 2005). Our data revealed that pancreas-bile duct ligation depleted the endogen GSH significantly compared to the control group. Treatment with FA 500 mg/kg elevated GSH levels in pancreatic tissue. Likewise, in a fluoride-induced oxidative hepatotoxicity model, it was shown that decreasing GSH levels in liver tissue increased significantly with 20 mg/kg FA treatment (Panneerselvam 2013).
TNF-α is a key regulator of other pro-inflammatory cytokines and leukocyte adhesion molecules expressed in acinar cells and acts as an activator of immune cells (Papachristou 2007). TNF-α has a central importance in acute pancreatitis, and TNF-α levels are thought to show a sensitivity of 96% in acute pancreatitis (Malleo 2007). The analysis of serum TNF-α levels showed that high TNF-α levels in the duct ligated saline-treated group decreased with FA treatment. FA treatment decreased the TNF-α levels of rats with the lipopolysaccharide-induced acute respiratory syndrome (Zhang 2018).
Acute pancreatitis is characterized by inflammation ad pancreas paracrine necrosis, pancreatic fat necrosis, hemorrhage, and inflammatory cell infiltration (Gül 2009). Insight into pancreatic cell death emerges related to necrosis or apoptosis mechanisms in these conditions (Esrefoglu 2012). In the study, intense destruction of the acini, parenchyma loss, edema, and leukocyte infiltration were observed in the pancreatic parenchyma of the saline-treated pancreatitis group. On the other hand, FA treatment groups had a significant decrease in the destruction of the acini, edema, and leukocyte infiltration. Another study showed that antioxidant treatment causes tissue healing in acute pancreatitis (Zhang 2008). The present study was also undertaken to evaluate the effect of FA on distant organ damage such as liver and lung damage due to acute pancreatitis. Liver damage occurs in 80% of acute pancreatitis patients and is associated with progression (Blamey 1984). Therefore, in this study, MDA and MPO levels, indicators of oxidative stress, were examined in liver tissue. Elevated MDA and MPO levels in rats with acute pancreatitis decreased significantly with the treatment of both doses of FA. Moreover, GSH levels were low in the liver in the acute pancreatitis group compared to the control group, and FA treatment prevented the depletion of GSH. Besides, vacuolization in hepatocytes, expending in sinusoids, vasocongestion in vein structures, and leucocyte infiltration in the periportal field in the liver were observed due to pancreatitis. On the other hand, treatment groups showed significant healing in liver tissue damage. Similar to our results, it was demonstrated that FA decreased leukocyte infiltration and hepatocellular degeneration in Diosbulbin B-induced liver injury (Niu 2016).
Lung damage emerges as the earliest and the most common in acute pancreatitis progression, leading to multiple organ damage (Leema 2018). Lung damage occurs in 10–25% of AP cases and is responsible for 60% of AP-related deaths (Muhs 2001, Shields 2002). Hence, histological evaluation showed that the pancreatitis group had fusion and deterioration in the alveolar structure, leukocyte infiltration, and edema. However, no improvement was observed in the treated groups. On the other hand, there was a significant increase in the MPO and MDA levels of the lung tissue in the pancreatitis group. Only the MPO level was reduced significantly in treatment with FA500 mg/kg. However, there was no significant decrease in the lipid peroxidation marker MDA level in the treated groups. Furthermore, depleted GSH levels in the pancreatitis group were restored with 500 mg/kg FA treatment. As a result, the slight improvement in the biochemical values was not observed at the tissue level in the lung.
In conclusion, FA reduced inflammation brought by pancreaticobiliary duct occlusion while lessening the severity of liver and lung damage. FA achieved anti-inflammatory effects in obstructive pancreatitis by preventing neutrophil infiltration, lipid peroxidation, endogen anti-oxidant GSH depletion, and cytokine production. Consequently, our results report for the first time that FA may have anti-oxidant and anti-inflammatory effects on acute pancreatitis by its neutrophil infiltration suppressing role and by its anti-oxidant efficacy.