The Role And Mechanism Of PERK In Autophagy And Apoptosis Of Spleen Lymphocytes In Rats With Severe Acute Pancreatitis

Objective: To investigate the role of PERK in autophagy and apoptosis of spleen lymphocytes in rats with severe acute pancreatitis(SAP)and its molecular mechanism.Methods: 50 adult male SPF SD rats were randomly divided into sham operation group(SO group)and SAP group.In the SAP group the SAP model was established by retrograde injection of 5% sodium taurocholate into the pancreaticobiliary duct.The rats in the SO group only turned the pancreas and closed the abdomen.The SO group was taken 24 hours after operation and the SAP group was taken at 6h 12 h 18h and 24 h after operation.HE staining was used to observe the pathological damage degree of pancreatic tissue and scored.Ultraviolet spectrophotometer was used to determine serum amylase and lipase.The autophagosomes of spleen lymphocytes were observed by transmission electron microscope.Flow cytometry was used to detect apoptosis rate and autophagy rate of spleen lymphocytes.The expression of PENK,autophagy-related genes(Beclin1 and LC3)and apoptosis-related gene Caspase-3 mRNA and protein in spleen lymphocytes were detected by RT-qPCR and Western blot.The serum of autophagy-related genes(Beclin1 and LC3)and apoptosis-related gene Caspase-3 were detected by ELISA.Results:(1)Compared with SO group,the expression level of PERK in SAP group was increased with time and it was statistical significance at each time point(P<0.05).(2)Compared with SO group,the number of autophagosomes of spleen lymphocytes were increased with time by using transmission electron microscope.Compared with SO group,the autophagy rate of spleen lymphocytes in SAP group was significantly increased with time and there was statistically significant at each time point(P<0.05).Compared with SO group,the apoptosis rate of spleen lymphocytes in SAP group were increased(P<0.05),reached the peak at 6h and then decreased but still higher than SO group.The expression of PERK protein in spleen lymphocytes was positively correlated with the autophagy rate and apoptosis rate of spleen lymphocytes(P<0.05).With the increase of PERK expression,the autophagy rate and apoptosis rate of spleen lymphocytes was increased,suggesting that the PERK signaling pathway is activated when SAP increases the autophagy and apoptosis of lymphocytes.(3)Compared with SO group,the expression of autophagy-related genes(Beclin1 and LC3)were significantly increased and there were statistical significance at each time point(P<0.05).The expression of PERK protein in spleen lymphocytes was positively correlated with the expression of autophagy-related genes(Beclin1 and LC3)(P<0.05).With the increase of PERK expression,the expression of autophagy-related genes(Beclin1 and LC3)in spleen lymphocytes were increased which may be an important reason for the enhancement of autophagy in spleen lymphocytes.Compared with SO group,the expression of apoptosis-related gene Caspase-3 was significantly increased and there was statistical significance at each time point(P<0.05).The expression of PERK protein in spleen lymphocytes was positively correlated with the expression of apoptosis-related gene Caspase-3(P<0.05).With the increase of PERK expression,the expression of apoptosis-related gene Caspase-3 in spleen lymphocytes was increased which may be an important reason for the enhancement of apoptosis in spleen lymphocytes.Conclusion:(1)The expression of PERK in spleen lymphocytes of SAP rats was significantly increased and autophagy and apoptosis of lymphocytes were increased.(2)The high expression of PERK increased the expression of autophagy-related genes(Beclin1 and LC3)and apoptosis-related gene Caspase-3 which may be an important reason for the autophagy and apoptosis of spleen lymphocytes.