The Study On The Effect Of Treating Non-alcoholic Fatty Liver Disease(NAFLD) Rats By High-intensity Interval Treadmill Training

Background: In recent years, the research of high intensity, intermittent form of training against lipid metabolism-related chronic disease, widespread concern of many researchers at home and abroad. Many studies have confirmed that high-intensity interval training have a good therapeutic effect on many chronic diseases, such as obesity, type 2 diabetes and high cholesterol, etc. Compared with the traditional low-intensity continuous training, the HIIT use the shorter time and with intermittent, it may be more likely to be accepted by the people. The formation mechanism of non-alcoholic fatty liver disease closely associated with obesity, insulin resistance, etc. So we assume that the high-intensity interval training on the treatment of NAFLD may be have effective.Objective: The research aims to study the effect of high-intensity interval treadmill training on the treatment of NAFLD by observing liver histology, body weight, body fat, cholesterol and other biochemical indicators. Compared with the same volume of training of moderate intensity continuous treadmill training, to explore the therapeutic effect that two ways type exercise on treatment the rats of model with NAFLD.Methods: There were 56 Wistar male rats. The animals were randomly divided into eight groups: rats in 12 weeks(C12 and H12) and 20 weeks(C20 and H20) control group were fed by standard diet and high-fat diet, 6 rats each group; the rats in group HE, were fed by high-fat diet for 12 weeks then exercised by high-intensity interval treadmill training(HIIT) for 8 weeks; the rats in group HDE, were fed by high-fat diet for 12 weeks then fed by standard diet and exercised by HIIT for 8 weeks; the rats in group HCE, were fed by high-fat diet for 12 weeks then exercised by moderate intensity continuous treadmill training(MICT) for 8 weeks; the rats in group HDCE, were fed by high-fat diet for 12 weeks then fed by standard diet and exercised by MICT for 8 weeks, 8 rats each group. HIIT project: 4 min exercise by the intensity of 85%-95% VO2 max and 4 min rest for a group, repeating seven groups. 5d/wk; MICT project: exercise by the intensity 60% VO2 max. Ensure the same distance should be achieved each group. After 12 and 20 weeks, killed the corresponding rats. Compared with liver histology, basic indicators and blood biochemical parameters what the rats of each group.Results:(1) Comparisons between group 12 weeks: the liver morphology and liver tissue in group C12 were normal. The rats in group H12, the liver was enlargement and was showed yellow color. Under the microscope, liver derangement board, with varying degrees of liver tissue steatosis. The higher ridit score than the group C12(p<0.01). The rats in group H12 have higher body weight, liver weight, liver index, each fat weight, and serum ALT, AST levels, but lower serum HDL-C compared with group C12. The difference significant or very significant(P<0.05 or p<0.01).(2) Comparisons liver histology between group 20 weeks: the liver morphology and liver tissue in group C20 were normal. The liver was enlargement and was showed yellow color in group H20, feeling greasy. Under the microscope, liver derangement board, severe, extensive bullous steatosis. Compared with group H20, after 8 weeks training, four exercise groups have a significantly reduced on liver volume. The color was showed between red and yellow. Liver panels arranged close to normal. The degree of hepatic steatosis were reduced, the differences were significant(P<0.01); compared with group HE, group HDE and HDCE were a less extent on steatosis, the differences were significant(P<0.05).(3) Comparisons biochemical indicators between group 20 weeks: group H20 have a higher serum TG, TC, LDL-C and FFA than group C20, the difference was significant or very significant(P<0.05 or P<0.01). Serum HDL-C, ALT and AST were no significant differences; after 8 weeks training, four exercise groups the level of serum TG, TC were lower compared with group H20, the difference was significant or very significant(P<0.05 or P<0.01). The serum LDL-C, ALT were lower in group HCE and HDCE, while group HE and HDE were no change. There were no significant effect on serum HDL-C in all groups.Conclusion:(1) High-intensity interval training for 8 weeks can be improved the hepatic steatosis, and there was had effectiveness in the treating of NAFLD in rats.(2) High-intensity interval training for 8 weeks had similar effectiveness in the management of NAFLD in rats when compared to moderate intensity continuous training.