Role of necroptosis in liver injury in rats undergoing autologous orthotopic liver transplantation

Objective To evaluate the role of necroptosis in liver injury in rats undergoing autologous orthotopic liver transplantation (AOLT). Methods Twenty-four SPF adult male Sprague-Dawley rats, weighing 250-280 g, were divided into 3 groups (n=8 each) using a random number table method: sham operation group (group S), AOLT group (group T) and necroptosis inhibitor necrostatin-1 group (group N). Rats were anesthetized using intraperitoneal 5% chloral hydrate 0.5 ml/100 g. A standard model of OALT was established as previously described by Yao et al.in T and N groups.Necrostatin-1 1.0 mg/kg and the equal volume of dimethyl sulfoxide were intraperitoneally injected at 30 min before surgery in N and T groups, respectively.Blood samples were collected from the inferior vena cava at 6 h after opening the portal vein (at 6 h after operation in group S) for determination of serum aspartate amino-transferase (AST) and alanine amino- transferase (ALT) concentrations.The livers were removed for examination of the pathological changes (with a light microscope) and for determination of the malondialdehyde (MDA) contents and superoxide dismutase (SOD) activity (using a spectrophotometer) and expression of receptor-interacting protein kinase-1 (RIPK1), RIPK3 and mixed lineage kinase domain-like (MLKL) in liver tissues (by Western blot). The damage to livers was evaluated using Suzuki′s scoring system. Results Compared with group S, the serum AST and ALT concentrations, Suzuki′s score of liver tissues and MDA content were significantly increased, the SOD activity was decreased, and the expression of RIPK1, RIPK3 and MLKL was up-regulated in group T (P<0.05). Compared with group T, the serum AST and ALT concentrations, Suzuki′s score of liver tissues and MDA content were significantly decreased, the SOD activity was increased, and the expression of RIPK1, RIPK3 and MLKL was down-regulated in group N (P<0.05). Conclusion Necroptosis is involved in liver injury in rats undergoing AOLT. Key words: Liver transplantation; Reperfusion injury; Necrosis