Protective Effect Of Curcumin On Hepatocytes In Septic Rats Based On Endoplasmic Reticulum Stress-mTOR-autophagy Pathway

OBJECTIVE: Based on the pathway of endoplasmic reticulum stress-m TOR-autophagy,this study further explored the mechanism of curcumin antagonizing hepatocyte apoptosis in sepsis rats through the pathway of endoplasmic reticulum apoptosis.METHODS: 100 male SD rats were randomly divided into 5 groups according to the random number table method,20 in each group,sham group,sepsis control group,solvent control group(DMSO group),low dose curcumin group(L-cur),high dose curcumin group(H-cur).Cecal ligation perforation(CLP)was used to establish sepsis rat model.The cecum was removed after open surgery in Sham group and then closed.In Control group,only CLP was performed.In DMSO group,intraperitoneal injection of solvent dimethyl sulfoxide(DMSO).In L-cur group,100mg/kg curcumin and DMSO were injected 10 minutes after CLP.In H-cur group,150mg/kg curcumin and DMSO were injected 10 minutes after CLP.Five rats were sacrificed 2,6,12 and 24 hours after operation.Hepatic histopathological changes were observed by HE staining.Serum levels of ALT,ALB and TBi L were detected by ELISA.The expression of ERS marker proteins CHOP,autophagy protein Beclin1 and m TOR were detected by Western blot.RESULTS:1.HE staining ResultsThe morphology of hepatocytes,sinusoids and lobules in Sham group were basically normal.Inflammatory cell infiltration and hepatocyte enlargement were observed in Control group and DMSO group at 2 hours after operation.With the prolongation of time,the extent of injury was further enlarged,cytoplasmic red staining deepened,and nucleus consolidation gradually disappeared.At 24 hours after operation,most of the hepatic lobules were necrotic,hepatic cord and sinusoids disappeared,and local residual swollen hepatocytes were observed.A large number of inflammatory cells infiltrated.The damage of L-cur group and H-cur group was significantly lighter than that of Control group and DMSO group at the same time point,and the damage degree of H-cur group was lighter than that of L-cur group.2.ELISA ResultsCompared with Sham group,the concentration of ALT,AST and TBi L in control group and DMSO group increased significantly at each time point,with statistical significance(P<0.05),and the concentration of ALT,AST and TBi L increased progressively with time prolongation.Compared with control group and DMSO group,the concentration of ALT,AST and TBi L in L-cur group and H-cur group decreased at each time point,with statistical significance(P<0.05).The concentration of ALT,AST and TBi L in H-cur group decreased more significantly than that in L-cur group at each time point(P<0.05).3.Western Blot Results3.1 ERS-related proteinsCompared with Sham group,the expression of CHOP protein in liver tissue of control group and DMSO group increased significantly(P<0.05).Compared with control group and DMSO group,the expression of CHOP protein in L-cur group and H-cur group decreased significantly(P<0.05),but there was no significant difference in the expression of CHOP protein between H-cur group and L-cur group(P>0.05).3.2 Autophagy-related ProteinsCompared with Sham group,the expression of Beclin1 protein in control group and DMSO group increased significantly(P<0.05);compared with control group and DMSO group,the expression of Beclin1 protein in L-cur group and H-cur group decreased significantly(P<0.05),but there was no significant difference in the expression of Beclin1 protein between H-cur group and L-cur group(P>0.05).Compared with Sham group,the level of m TOR protein in liver tissue of control group and DMSO group decreased significantly(P<0.05);compared with control group and DMSO group,the expression of m TOR protein in L-cur group and H-cur group increased significantly(P<0.05),but there was no significant difference in the expression of m TOR protein between H-cur group and L-cur group(P>0.05).CONCLUSION: Endoplasmic reticulum stress and autophagy are involved in the apoptotic process of hepatocytes in sepsis rats.Curcumin may protect hepatocytes and improve liver function by inhibiting the expression of endoplasmic reticulum stress apoptotic promoter CHOP and autophagic Beclin1 protein and increasing the level of m TOR.Endoplasmic reticulum stress-m TOR-autophagy pathway may be one of the mechanisms of curcumin that antagonizing hepatocyte apoptosis in sepsis rats.