ABSTRACT
Objective To evaluate the role of necroptosis in liver injury induced by intestinal ischemia-reperfusion (I/R) in rats.Methods Thirty-two healthy adult male Sprague-Dawley rats,weighing 250-300 g,were divided into 4 groups (n=8 each) using a random number table:sham operation group (S group),I/R group,specific necroptosis inhibitor necrostatin-1 group (N group) and dimethyl sulfoxide (DMSO) group (D group).Intestinal I/R was produced by occlusion of the superior mesenteric artery for 1.5 h followed by 6 h of reperfusion.The superior mesenteric artery was only isolated but not ligated in group S.At 30 min before ischemia,necrostatin-1 1 mg/kg (diluted to 200 μl in DMSO) was intraperitoneally injected in group N,while the equal volume of DMSO was given instead in group D.The animals were sacrificed at the end of reperfusion,livers were removed for examination of the pathological changes with a light microscope,and the severity of liver injury was evaluated using the Eckhoff's scale score.Blood samples were collected from the cardiac apex for determination of serum alanine transaminase (ALT) concentrations by enzyme-linked immunosorbent assay.The expression of receptor-interacting protein kinase 1 (RIP1),RIP3 and high-mobility group box 1 protein (HMGB1) in cytoplasm of hepatocytes was detected by Western blot.The location of RIP1 and RIP3 in liver tissues was determined by immunohistochemistry,and the translocation of HMGB1 from nucleus to cytoplasm was tested by immunofluorescence.Results Compared with group S,the Eckhoff's scale score of liver tissues and serum ALT concentration were significantly increased,the expression of RIP1,RIP3 and HMGB1 in liver tissues was up-regulated (P＜0.05),and the hepatocytes in which RIP1 and RIP3 were highly expressed in the portal area were increased in group I/R.Compared with group I/R,the Eckhoff's scale score of liver tissues and serum ALT concentration were significantly decreased,the expression of RIP1,RIP3 and HMGB1 in liver tissues was down-regulated (P＜0.05),and the hepatocytes in which RIP1 and RIP3 were highly expressed in the portal area were decreased in group N,and no significant changes were found in the variables mentioned above in group D (P＞0.05).HMGB1 was expressed in the nucleus of hepatocytes in the portal area in group S;a large number of HMGB1 in hepatocytes in the portal area was translocated to cytoplasm in I/R and D groups;a small number of HMGB1 in hepatocytes in the portal area was translocated to cytoplasm in group N.Conclusion Necroptosis is involved in intestinal I/R-induced liver injury in rats.