Calpain-1 deficiency alleviates oxidative stress and hepatic injury in ApoE-deficient mice with MASH.

BACKGROUND

Metabolic dysfunction-associated steatohepatitis (MASH) is a critical stage of metabolic dysfunction-associated fatty liver disease (MAFLD) characterized by hepatocyte ballooning, inflammatory infiltration, and fibrosis, often accompanied by oxidative stress, lipotoxicity, and apoptosis. Calpain-1 is involved in the regulation of oxidative stress and inflammation in cellular stress responses, but its role in MASH remains unclear.

METHODS

This study established MASH models in ApoE knockout (ApoE KO) and ApoE/calpain-1 double knockout (AxC DKO) mice. Serum lipids and liver function were assessed. Hepatic lipid deposition was evaluated by magnetic resonance imaging (MRI) and Oil Red O staining. Liver injury and inflammation were examined by H&E staining and inflammatory cytokine assays. Hepatic oxidative stress was assessed by measuring reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD) activity, and the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio. Proteomic analysis was performed to explore the underlying mechanisms.

RESULTS

Compared with C57 mice, ApoE KO mice exhibited hyperlipidemia, liver dysfunction, increased lipid deposition, elevated ROS and MDA levels, decreased SOD activity and GSH/GSSG ratio, and exacerbated hepatic inflammation. Compared with ApoE KO mice, AxC DKO mice exhibited improved liver function, reduced ROS and MDA, increased SOD activity and GSH/GSSG ratio, and reduced inflammatory markers, without altering hepatic lipid deposition. Proteomic analysis revealed that calpain-1 deficiency partially restored antioxidant protein expression, attenuated the upregulation of CYP450 metabolic enzymes, normalized mitochondrial protein abnormalities, and reduced inflammation-related protein expression.

CONCLUSIONS

Calpain-1 deficiency alleviates MASH-related liver injury by modulating redox homeostasis, reducing oxidative stress and inflammatory, independent of directly lowering hepatic lipid accumulation.