SUMMARY
Objective Aerobic exercise can improve liver metabolic diseases such as non-alcoholic fatty liverdisease (NAFLD), but the molecular mechanism is not completely clear, which limits the applicationof aerobic exercise in the treatment and improvement of NAFLD. In this paper, the effects of aerobicexercise on the expression levels of important genes regulating fatty acid metabolism in the liver ofNAFLD rats were studied in order to explore the possible molecular mechanism of aerobic exerciseregulating hepatic fatty acid metabolism.Methods 1. Animal grouping. 36 male Sprague Dawley (SD) rats aged 21 days old were randomlydivided into three groups after 1 week of adaptive feeding: 10 in the normal diet quiet group (NCgroup), 10 in the high-fat diet quiet group (HC group) and 16 in the high-fat diet exercise group (HTgroup). 2. Training arrangements. After 12 weeks, the rats in the HT group underwent 8 weeks ofaerobic exercise with a training intensity of 25m/min, and continued exercise for 1h/d, 6d/w for atotal of 8 weeks. 3. Sample collection. After an overnight fast, rats in the three groups were weighedand anesthetized with an intraperitoneal injection of 10% chloral hydrate (0.3 ml/100 g bodyweight). Blood samples were collected from the aortaventralis, centrifuged, and kept frozen at -80 °Cfor chemical assays. The rat liver was removed, frozen in liquid nitrogen, and stored in a -80 °Cfreezer. 4. Serum lipid concentration and liver function detection. Serum levels of total cholesterol(TC), triglyceride (TG), high density lipoprotein cholesterol (HDL-C), low density lipoproteincholesterol (LDL-C), free fatty acid (FFA), aspartate aminotransferase (AST) and alanineaminotransferase (ALT) were detected in three groups of rats. 5. Detection of expression levels offatty acid metabolism related genes in liver. The expression levels of AMP-activated protein kinase(AMPK), silence information regulator 1 (SIRT1), peroxisome proliferator-activated receptor ?coactivator 1a (PGC-1a) in rat liver were detected by SYBR Green real-time PCR. 6. Data statistics.Results were expressed in the form of mean±standard deviation. Spss17.0 statistical software wasused to conduct one-way ANOVA to compare the differences between the groups, p<0.05 indicatessignificant difference between groups.Results 1. Effects of aerobic exercise on Blood lipids and liver function. The serum levels of TC, TG,LDL-C, FFA, AST and ALT in HC group were significantly higher than those in NC group (p < 0.05),while HDL-C level was significantly lower (p < 0.05). The serum concentrations of TC, TG, LDL-C, FFA,AST and ALT in HT group were significantly lower than those in HC group (p < 0.05), while HDL-Clevel was significantly higher (p < 0.05). 2.Effects of aerobic exercise on the expression of fatty acidmetabolism regulatory genes in liver of rats. The mRNA expression levels of AMPK, SIRT1 and PGC-1a in liver of HC group were significantly lower than those of NC group (p < 0. 05). While the mRNAexpression levels of AMPK, SIRT1 and PGC-1 a in liver of HT group were significantly higher thanthose of HC group (p < 0. 05).Conclusions Aerobic exercise can improve serum lipid concentration and liver function in NAFLDrats. It increased the consumption of ATP, led to an increase in AMP/ATP ratio, enhanced the mRNAexpression of AMPK, SIRT1 and PGC-1a, activated AMPK - SIRT1 - PGC-1a signaling pathway,reduced hepatic fat synthesis and accelerated fatty acid oxidation in NAFLD rats liver.