Background: Nonalcoholic fatty liver disease (NAFLD) represents one of the most common forms of liver disease worldwide, and it is always regarded as a consequence of a sedentary, food-abundant lifestyle, sitting for an extended time, and a low physical activity level, which often coincide with chronic and long-lasting psychological stress. A Chinese medicine Sinisan (SNS) may be a potential formula for treating this kind of disease.
Methods: In this study, a long-term chronic restraint stress protocol was used to investigate the mechanism underlying stress-induced NALFD. To investigate the effect of SNS treatment on stress-induced NAFLD, we measured the liver and serum values of total cholesterol (TC), triglyceride (TG), liver free fatty acids (FFA), low-density lipoprotein, superoxide dismutase, tumor necrosis factor-α, malondialdehyde, interleukin (IL)-6, and serum values of aspartate aminotransferase (AST), alanine aminotransferase (ALT), and alkaline phosphatase. Results are shown as a mean ± standard deviation. Significant differences between the groups were evaluated using the Student t-test. For multiple comparisons, one-way analysis of variance (ANOVA) was used. If the results of ANOVA indicated significant differences, post hoc analysis was performed with the Tukey test or Dunnett test, and p < 0.05 was considered statistically significant.
Results: Long-term chronic stress led to steatosis and non-alcoholic steatohepatitis. Additionally, SNS treatment significantly increased body weight gain (p < 0.01) and sucrose preference (p < 0.001), and it reduced the liver values of TC, TG, and FFA (p < 0.05). SNS also reduced the serum values of AST and ALT (p < 0.001), and the liver value of IL-6 (p < 0.01).
Conclusions: This study's results demonstrate that psychological stress may be a significant risk factor of NAFLD. Furthermore, the traditional Chinese medicine formula SNS may have some beneficial effect in antagonizing psychological stress and stress-related NAFLD.
Keywords: Chronic stress; NAFLD; Oxidative stress; Psychological stress; Sinisan; TCM.