Heavy metal contamination including mercury (Hg) has become one of the most serious environmental problems facing humans and other living organisms. Here, the hepatoprotective effects of Z. spina-christi leaf extract (ZCE) against inorganic mercury salt (mercuric chloride; HgCl2)-induced hepatotoxicity model was investigated in rats. Mercury concentration, liver function markers, oxidative stress markers, inflammation, cell death indicators, and histopathology were assessed. ZCE protected against HgCl2-induced hepatotoxicity, decreased Hg concentration, lipid peroxidation, and nitric oxide, increased glutathione, superoxide dismutase, catalase, and glutathione recycling enzymes (peroxidase and reductase), and upregulated nuclear factor-erythroid 2-related factor 2 (Nrf2) gene expression in HgCl2-intoxicated rat hepatic tissue. Nrf2 downstream gene and heme oxygenase-1 were also upregulated, confirming that hepatoprotection by ZCE against HgCl2-induced liver damage involved activation of the Nrf2/antioxidant response element pathway. ZCE also decreased the expression and production of pro-inflammatory cytokines and pro-apoptotic proteins and increased anti-apoptotic protein Bcl-2. Immunohistochemical analysis of liver tissues of HgCl2-treated rats confirmed the alternations of apoptotic-related protein expression. Our data demonstrated that post-administration of ZCE attenuated HgCl2-induced liver damage by activating the Nrf2/HO-1 signaling pathway. Therefore, administering this extract may be a novel therapeutic strategy for inorganic mercury intoxication.
Keywords: Liver; Mercuric chloride; Nuclear factor-erythroid-2-related factor 2; Ziziphus spina-christi.