Effect of liver-regulating and spleen-strengthening method on lipid metabolism and expression of microtubule-associated protein light chain 3B in a rat model of nonalcoholic fatty liver disease

Objective To investigate the effect of the liver-regulating and spleen-strengthening method on lipid metabolism and expression of microtubule-associated protein light chain 3 B (LC3B) in a rat model of nonalcoholic fatty liver disease (NAFLD) , as well as the mechanism of this method in the treatment of NAFLD.Methods A total of 30 clean male Sprague-Dawley rats were randomly divided into control group, model group, and liver-regulating and spleen-strengthening group, with 10 rats in each group.The rats in the model group and the liver-regulating and spleen-strengthening group were given high-fat diet for 12 weeks.The rats in the liver-regulating and spleen-strengthening group were given liver-regulating and spleen-strengthening prescription 2 ml·100 g-1·d (five times the dose for adults) by gavage, and those in the control group were given normal diet and an equal volume of normal saline by gavage.The rats were sacrificed at the end of week 12, and blood and liver samples were collected to measure the serum levels of alanine aminotransferase (ALT) , aspartate aminotransferase (AST) , triglyceride (TG) , total cholesterol (TC) , high-density lipoprotein cholesterol (HDL-C) , and low-density lipoprotein cholesterol (LDL-C) .HE staining was performed to observe hepatic steatosis, and immunohistochemistry was used to measure the change in the expression of LC3B in liver tissue.A one-way analysis of variance was used for comparison of continuous data between multiple groups, and the least significant difference t-test was used for further comparison between two groups; the chi-square test was used for comparison of categorical data between groups; the Kruskal-Wallis H test was used for comparison of ranked data between multiple groups, and the Mann-Whitney U test was used for further comparison between two groups.Results HE staining showed that there were significant differences in the degree of hepatocyte fatty degeneration and score of inflammatory activity between the model group and the control group (both P < 0.001) ; compared with the model group, the liver-regulating and spleen-strengthening group had significant reductions in the degree of hepatocyte fatty degeneration and score of inflammatory activity (both P < 0.01) .Compared with the control group, the model group had significant increases in the serum levels of ALT, AST, TG, TC, HDL-C, and LDL-C (all P < 0.001) ; compared with the model group, the liver-regulating and spleen-strengthening group had significant reductions in the serum levels of ALT, AST, TG, TC, and LDL-C (all P < 0.05) .Compared with the control group, the model group had a slight increase in the expression of LC3B in liver tissue (χ2= 1.250, P > 0.05) ; compared with the model group, the liver-regulating and spleen-strengthening group had a significant increase in the expression of LC3B in liver tissue (χ2= 5.051, P < 0.05) .Conclusion The liver-regulating and spleen-strengthening method can improve liver function and blood lipids in experimental male Sprague-Dawley rats with NAFLD, possibly by increasing the level of autophagy in liver tissue.