Effect Of IRE1/XBP1 On Apoptosis Of Spleen Lymphocytes In Rats With Severe Acute Pancreatitis

Objective: To investigate the effect of IRE1 / XBP1 on apoptosis of spleen lymphocytes in rats with severe acute pancreatitis(SAP)Methods: 30 SPF grade adult male SD rats were randomly divided into sham operated group(SO group),SAP 6h group and SAP 12 h group,10 rats in each group.SAP model was established by retrograde injection of 5% sodium taurocholate solution into pancreaticobiliary tract,SO group rats only turn the pancreas and then close the abdomen as the experimental control group.Serum amylase and lipase in all experimental rats were detected by ultraviolet spectrophotometer,HE staining was used to observe the pathological severity of pancreatic tissue in rats and the pathological score was determinated,The apoptosis rate of splenic lymphocytes were detected by flow cytometry,apoptosis morphology of spleen lymphocytes were observed by transmission electron microscopy,mRNA and protein expression of Bax and Caspase-3 in rat spleen lymphocytes were observed by RT-q PCR and Western blot.Results:(1)Compared with SO group,the apoptosis rate of spleen lymphocytes in SAP group was significantly higher,peaked at 6h,slightly decreased at 12 h,but still higher than SO group,the difference was statistically significant(P < 0.05).(2)The mRNA and protein expression of IRE1 and XBP1 in spleen lymphocytes of rats in the SO group were low.Compared with the SO group,the expression levels of IRE1 and XBP1 in the SAP group were increased,and the increase was more significant in the SAP 12 h group,with a statistically significant difference(P < 0.05).(3)The expression of Bax,caspase-3 mRNA and protein in spleen lymphocytes of SO group rats was low,Compared with SO group,the expression levels of Bax and Caspase-3 in spleen lymphocytes of SAP group were significantly increased,It reached the peak at 6h,decreased slightly at 12 h,but still higher than that of SO group,the difference was statistically significant(P < 0.05)(4)The expression levels of IRE1 and XBP1 in spleen lymphocytes of rats in SAP 6h and 12 h groups were positively correlated with the expression levels of Bax and caspase-3(all P < 0.05).(5)There was a positive correlation between the expression of IRE1 and XBP1 protein and the apoptosis of spleen lymphocytes in SAP 6h and 12 h groups(all P < 0.05),With the increase of expression level of IRE1 and XBP1,the lymphocyte withering rate increased.Conclusion: The expression level of IRE1 / XBP1 in spleen lymphocytes of SAP rats increased significantly,Lymphocyte apoptosis increased;Overexpression of IRE1 / XBP1 results in an increased expression of Bax and caspase-3,that may be an important reason for the increased apoptosis of spleen lymphocytes in SAP rats.