[Gynostemma pentaphyllum saponins alleviate non-alcoholic fatty liver disease in rats by regulating intestinal flora and short-chain fatty acid metabolism].

This study aimed to explore the effects of Gynostemma pentaphyllum saponins(GPs) on non-alcoholic fatty liver disease(NAFLD) induced by high-fat diet in rats and reveal the underlying mechanism. The NAFLD model rats were prepared with high-fat diet. Forty male Sprague Dawley(SD) rats were randomly assigned into the control group, model group, and low-, moderate-, and high-dose GPs(50, 100, and 150 mg·kg~(-1), respectively) groups. After intragastric administration for 8 continuous weeks, we determined the body weight, liver weight, the levels of total cholesterol(TC), triglyceride(TG), low-density lipoprotein cholesterol(LDL-c), high-density lipoprotein cholesterol(HDL-c), alanine aminotransferase(ALT), and aspartate aminotransferase(AST) in serum, and the levels of TC, TG, malondialdehyde(MDA), superoxide dismutase(SOD), catalase(CAT), and interleukin 6(IL-6) in the liver. Furthermore, we observed the pathological changes of liver tissue by oil red O staining and hematoxylin-eosin(HE) staining, sequenced the 16 S rRNA of the intestinal flora in rat feces, and determined the content of short-chain fatty acids in rat feces. The results showed that GPs inhibited the excessive weight gain of high-fat diet-induced NAFLD in rats, reduced the liver weight, lowered the TC, TG, LDL-c, AST, and ALT levels in serum(P<0.05), and rose the HDL-c level in serum(P<0.01). GPs relieved the liver damage caused by high-fat diet, mainly manifested by the lowered levels of TC, TG, MDA, and IL-6 in the liver(P<0.01) and elevated levels of CAT and SOD in the liver. Furthermore, GPs reversed the intestinal flora disorder caused by high-fat diet, restored the diversity of intestinal flora, increased the relative abundance of Bacteroides, and reduced the relative abundance of Firmicutes and the ratio of Firmicutes to Bacteroides. Moreover, GPs promoted the proliferation of beneficial bacteria such as Akkermansia, Bacteroides, and Parabacteroides, and inhibited the growth of harmful bacteria such as Desulfovibrio, Escherichia-Shigella, and Helicobacter. GPs increased the content of short-chain fatty acids(acetic acid, propionic acid, and butyric acid)(P<0.01). These findings indicate that GPs can alleviate the high-fat diet-induced NAFLD in rats via regulating the intestinal flora and short-chain fatty acid metabolism.