Carbon tetrachloride-induced liver damage in asialoglycoprotein receptor-deficient mice

The asialoglycoprotein (ASGP) receptor is an abundant hepatocyte-specific receptor involved in receptor-mediated endocytosis. This receptor's abundance and function is decreased by chronic ethanol administration prior to the appearance of pathology such as necrosis or inflammation. Hence, this study aimed to determine if ASGP receptor function is required to protect against liver injury by utilizing a knockout mouse model lacking functional ASGP receptor in the setting of carbon tetrachloride (CCl4) hepatotoxicity. Briefly, ASGP receptor-deficient (RD) mice and wild-type (WT) mice were injected with 1 ml/kg body weight of CCl4. In the subsequent week, mice were monitored for liver damage and pathology (aspartate transaminase (AST), alanine transaminase (ALT) and light microscopy). The consequences of CCl4 injection were examined by measuring α-smooth muscle actin (α-SMA) deposition, contents of malondialdehyde and the percentage of apoptotic hepatocytes. After CCl4 injection, RD mice showed increased liver pathology together with significantly increased activities of AST and ALT compared to that in WT mice. There were also significantly more apoptotic bodies, lipid peroxidation and deposition of α-SMA in RD mice versus WT mice following CCl4 injection. Since these two mouse strains only differ in whether or not they have the ASGP receptor, it can be concluded that proper ASGP receptor function exerted a protective effect against CCl4 toxicity. Thus, receptor-mediated endocytosis by the ASGP receptor could represent a novel molecular mechanism that is responsible for subsequent liver health or injury.