Influence of glutamine on pancreatic blood flow and apoptosis of pancreatic acinar in rats with severe acute pancreatitis

Effects of glutamine alone on the acute necrotizing pancreatitis in rats

BACKGROUND

The effects of the glutamine on the acute pancreatitis are controversial in the clinical and experimental studies. The aim of this study was to investigate the influence of glutamine alone on acute necrotizing pancreatitis (ANP) induced by glycodeoxycholic acid in rats.

MATERIAL AND METHODS

Fifty-two male Sprague-Dawley rats weighing 300-350 g were used. Rats were divided into four groups as sham + saline, sham + glutamine, ANP + saline and ANP + glutamine. ANP in rats was induced by glycodeoxycholic acid. The extent of acinar cell injury, mortality, systemic cardiorespiratory variables, functional capillary density, renal/hepatic functions, and changes in some enzyme markers for pancreatic and lung tissue were investigated during ANP in rats.

RESULTS

The induction of ANP resulted in a significant increase in the mortality rate, pancreatic necrosis, and serum activity of amylase, alanine aminotransferase, interleukin-6, lactate dehydrogenase in bronchoalveolar lavage fluid, serum concentration of urea, and tissue activity of myeloperoxidase and malondialdehyde in the pancreas and lung, and a significant decrease in concentrations of calcium, blood pressure, urine output, pO2, and functional capillary density. The use of glutamine alone improved these changes.

CONCLUSIONS

Glutamine demonstrated beneficial effect on the course of ANP in rats. Therefore, it may be used by itself in the treatment of acute pancreatitis.

Amino acid transporters expression in acinar cells is changed during acute pancreatitis

Pancreatic acinar cells accumulate amino acids against a marked concentration gradient to synthesize digestive enzymes. Thus, the function of acinar cells depends on amino acid uptake mediated by active transport. Despite the importance of this process, pancreatic amino acid transporter expression and cellular localization is still unclear. We screened mouse pancreas for the expression of genes encoding amino acid transporters. We showed that the most highly expressed transporters, namely sodium dependent SNAT3 (Slc38a3) and SNAT5 (Slc38a5) and sodium independent neutral amino acids transporters LAT1 (Slc7a5) and LAT2 (Slc7a8), are expressed in the basolateral membrane of acinar cells. SNAT3 and SNAT5, LAT1 and LAT2 are expressed in acinar cells. Additional evidence that these transporters are expressed in mature acinar cells was gained using acinar cell culture and acute pancreatitis models. In the acute phase of pancreatic injury, when acinar cell loss occurs, and in an acinar cell culture model, which mimics changes occurring during pancreatitis, SNAT3 and SNAT5 are strongly down-regulated. LAT1 and LAT2 were down-regulated only in the in vitro model. At protein level, SNAT3 and SNAT5 expression was also reduced during pancreatitis. Expression of other amino acid transporters was also modified in both models of pancreatitis. The subset of transporters with differential expression patterns during acute pancreatitis might be involved in the injury/regeneration phases. Further expression, localization and functional studies will follow to better understand changes occurring during acute pancreatitis. These findings provide insight into pancreatic amino acid transport in healthy pancreas and during acute pancreatitis injury.

Baicalin protects thymus of rats with severe acute pancreatitis

To study the protective role of Baicalin on rats thymus with severe acute pancreatitis (SAP). The SAP rats were randomly assigned to the model control, Baicalin treated and Octreotide treated groups. Normal rats were assigned to the sham-operated group. The rat survival rates, pathological changes of thymus, apoptotic indexes and expression levels of NF-kappaB, Bax, Bcl-2, Caspase-3 and P-selectin of all groups were observed and recorded at 3, 6 and 12 h after operation, respectively. Rat survival rates were significantly higher in both Baicalin- and Octreotide-treated groups than those in the model control group at 12 h (P < 0.05). The thymus pathological score was significantly lower in Baicalin treated group than in control group at 3 and 12 h (P < 0.05). The expression of NF-kappaB, Bax and Bcl-2 in thymus tissue was negative in all groups. At 3 h after operation, the staining intensity, positive staining rate and intensity of Caspase-3 protein in the thymuses of the Baicalin treated group were significantly higher than those in the model control group (P < 0.01). At different time points after operation, no marked difference was observed in the staining intensity of P-selectin protein between the Baicalin treated group and the model control group (P > 0.05). At 6 h after operation, the positive staining rate and intensity of P-selectin protein in the Baicalin treated group was significantly lower than those in the model control group (P < 0.05). The apoptotic indexes were significantly higher in treated group than in model control group at 6 h (P < 0.05). Baicalin has a protective role on the thymus of SAP rats, and its effect of decreasing inflammatory mediators level in blood, inhibiting P-selectin expression and inducing apoptosis of thymocytes may involve in the mechanism of its protective role.

Protecting effects of a large dose of dexamethasone on spleen injury of rats with severe acute pancreatitis

BACKGROUND AND AIMS

To explore the protecting effects and mechanisms of dexamethasone on spleen injury in rats with severe acute pancreatitis (SAP).

METHODS

The rats were randomly divided into a model control group, treated group and sham-operated group. The contents of plasma endotoxin, serum NO, phospholipase A(2) enzyme (PLA(2)) and endothelin-1 (ET-1) were determined. The mortality rate, pathological changes and changes of Bax and Bcl-2 protein expression levels and apoptotic indexes in the spleen of rats were observed in all groups, respectively, at 3, 6 and 12 h after operation.

RESULTS

Although the survival rate was significantly higher in the treated group than in the model control group, there was no significantly different between them (P > 0.05). The expression levels of Bax and Bcl-2 proteins and apoptotic indexes were significantly higher in the treated group than in the model control group at different time points (P < 0.05 or P < 0.01) while other blood indexes contents and pathological severity scores of spleen were significantly lower in the treated group than in the model control group (P < 0.05, P < 0.01 or P < 0.001).

CONCLUSION

Dexamethasone can protect spleen from injury during SAP mainly by reducing the content of inflammatory mediators in blood.

Advances in the pathogenesis of acute pancreatitis

Acute pancreatitis (AP), especially acute necrotizing pancreatitis, is a common clinical disorder presenting as an acute abdomen. As AP is often complicated with systemic inflammatory response syndrome and multiple organ failure, the overall mortality rate in AP patients is high. At present, the research on the pathogenesis of AP has attracted wide attention though it has not been fully clarified yet. Of many theories to explain the pathogenesis of AP, "the theory of self-digestion of the pancreas" is the dominant hypothesis. In recent years, concerns have also been raised over "the theory of inflammatory mediators", "the theory of intestinal bacterial translocation", "the theory of apoptosis" and "the theory of calcium overload of pancreatic acinar cells". In addition, extensive research on the relationship between hyperlipidemia, especially high triglycerides (TG), and AP has also been conducted. In this article, we will review the recent advances in the pathogenesis of AP.

Study on protecting effects of Baicalin and Octreotide on hepatic injury in rats with severe acute pancreatitis

AIM: To investigate the protective effects and mechanisms of Baicalin and Octreotide on hepatic injury in rats with severe acute pancreatitis (SAP).

METHODS: The SAP rat models were prepared and randomly assigned to the model control group, Baicalin treated group, and Octreotide treated group while other healthy rats were assigned to the sham-operated group. Rat mortality, levels of ALT, AST, liver and pancreas pathological changes in all groups were observed at 3, 6 and 12 h after operation. Tissue microarray (TMA) sections of hepatic tissue were prepared to observe expression levels of Bax, Bcl-2 protein and Caspase-3, and changes of apoptotic indexes.

RESULTS: Rat survival at 12 h, expression levels of Bax, Caspase-3 protein and apoptotic indexes of liver were all significantly higher in treated groups than in model control group. While the liver and pancreas pathological scores, contents of ALT, AST, and expression levels of Bcl-2 protein were all lower in treated groups than in the model control group.

CONCLUSION: Both Baicalin and Octreotide can protect rats with SAP by decreasing the contents of ALT, AST and expression levels of Bcl-2 protein, and improving the expression levels of Bax protein, Caspase-3 protein, and inducing apoptosis.