THE PROTECTIVE EFFECT OF DEXMEDETOMIDINE ON THE LIVER INJURY IN SEPSIS THROUGH INHIBITION OF NECROPTOSIS

ABSTRACT Background: Sepsis-induced liver injury leads to extensive necroptosis in hepatocytes, which is the main factor of liver dysfunction. This study aims to investigate the protective effect of dexmedetomidine (DEX) on septic liver and to explore whether its molecular mechanism is related to the modulation of necroptosis. Methods: The model of septic liver injury was induced by cecal ligation and puncture (CLP) in rats. DEX and necrostatin-1(Nec-1), a specific antagonist of necroptosis, were administered 1 h before CLP. The levels of arterial blood gas, serum aspartate aminotransferase, and alanine aminotransferase were measured at 6, 12 and 24 h after CLP. The survival rate was observed 24 h after CLP. Liver pathological changes and apoptosis, the contents of IL-6 and TNF-α in liver tissue homogenates, the ROS content in liver tissue, and the expression levels of RIP1, RIP3, MLKL, and HMGB1 were detected. Results: At 6, 12, and 24 h after CLP, the levels of aspartate aminotransferase, and alanine aminotransferase levels increased, and liver enzyme levels gradually increased with the progression of sepsis. In arterial blood gas analysis, P a O 2 gradually decreased and lactic acid concentration gradually increased during these three periods. The morphological impairment of liver tissues, increased apoptosis, elevated inflammatory factors (IL-6 and TNF-α), increased ROS level, and necroptosis components (RIP1, RIP3, MLKL, and HMGB1) were all observed in sepsis rats. However, these injuries can be ameliorated by pretreatment with DEX. Meanwhile, Nec-1 pretreatment also reduced the expression of RIP1, RIP3, MLKL, HMGB1, and ROS level. Conclusion: Our study suggests that DEX alleviates septic liver injury, and the mechanism is associated with the inhibition of necroptosis.