Effect of metformin on hepatic ischemia-reperfusion injury-induced endoplasmic reticulum stress: A mechanistic exploration based on molecular docking and experimental validation.

INTRODUCTION: Hepatic ischemia-reperfusion injury (HIRI) is a major clinical challenge with limited therapeutic options. Metformin (Met) has demonstrated protective effects against ischemia-reperfusion (IR) injury in other organs by modulating endoplasmic reticulum (ER) stress, but its role and mechanism in HIRI remain unclear. METHODS: A mouse HIRI model was established following Met pre-treatment, with six mice included in each group. HIRI was assessed by measuring serum injury markers, examining histopathological changes, and evaluating apoptosis. ER stress markers were analyzed by western blot. Molecular docking predicted interactions between Met and ER stress proteins. AML12 hepatocytes under hypoxia/reoxygenation (H/R) were treated with Met, VER-155008 (VER), and/or CDN1163, followed by analysis of key cell parameters: viability, lactate dehydrogenase (LDH) release, apoptosis, and calcium flux. In vitro experiments were performed as three independent biological experiments. RESULTS: Met pre-treatment significantly attenuated IR-induced hepatic injury, evidenced by reduced serum injury markers, histopathological changes, and hepatocyte apoptosis (p < 0.05). Met also suppressed the HIRI-induced upregulation of ER stress proteins, including GRP78, p-PERK, p-IRE1α, and CHOP (p < 0.05). Molecular docking predicted a potential interaction of Met with GRP78. In H/R-induced AML12 hepatocytes, Met, VER, and CDN1163 similarly improved viability and reduced LDH release and apoptosis (p < 0.05). The protective effect of Met was not observed in the presence of VER, while it showed synergistic efficacy with CDN1163. Notably, Met did not markedly reduce H/R-induced cytosolic Ca2+ accumulation but effectively inhibited H/R-induced ER stress activation. CONCLUSIONS: Met protects against HIRI by suppressing ER stress, and this effect is associated with GRP78 functional regulation without obvious correction of cytosolic Ca2+ accumulation. These findings suggest that GRP78-related ER stress regulation may represent a potential mechanism underlying the hepatoprotective effect of Met.