Chronic stress induces steatohepatitis while decreases visceral fat mass in mice

Prolonged stress leads over time to allostatic load on the body and is likely to exacerbate a disease process. Long-term of stress exposure is one of a risk factor for metabolism-related diseases such as obesity and type 2 diabetes. However, the relationship between chronic stress and non-alcoholic fatty liver disease (NAFLD) remain unknown.

To address the hypothesis that chronic stress associate to NAFLD development, we subjected C57bl/6 mice to electric foot shock and restraint stress for 12 weeks to set up chronic stress model. Then the serum and hepatic triglyceride (TG), total cholesterol (TC) were measured. Hepatic HE and Oil red O staining were used to specify the state of the NAFLD. To investigate whether inflammation takes part in the stress-induced NAFLD process, related visceral fat, serum and hepatic inflammatory factors were measured.

We observed that chronic stress led to an overall increase of hepatic triglyceride and cholesterol while decreasing body weight and visceral fat mass. Microvesicular steatosis, lobular inflammation and ballooning degeneration were seen in stress liver section. This effect was correlated with elevated hepatic and serum inflammatory factors. Although the amount of visceral fat was decreased in stress group, various adipocytokines were elevated.

We showed that chronic stress is associated to NAFLD and chronic inflammation in visceral fat, though food intake and visceral fat mass were decreased. These results may contribute to better understanding of the mechanism from steatosis to steatohepatitis, and propose a novel insight into the prevention and treatment of NAFLD.