Effects of low-calorie diet on steatohepatitis in rats with obesity and hyperlipidemia

AIM: To evaluate the effects of low calorie diet (LCD) on nonalcoholic steatohepatitis (NASH) in rats with obesity and hyperlipidemia. METHODS: 29 Sprague-Dawley (SD) rats were randomly divided into three groups. The animals in control (n=9) and NASH group (n=10) were fed on standard rat diet and high fat diet respectively for 12 weeks, ten rats in LCD group were fed on high fat diet for 10 weeks and then low calorie diet for 2 weeks. At the end of the experiment, body weight, abdominal adipose content, liver function, and hepatopathological changes were examined to evaluate the effect of different feeding protocols on the experimental animals. RESULTS: There was no death of animal in the experimental period. All rats in the NASH group developed steatohepatitis according to liver histological findings. Compared with the control group, body weight (423.5+/-65.2 vs 351.1+/-43.0 g, P<0.05), abdominal adipose content (14.25+/-1.86 vs 9.54+/-1.43, P<0.05), liver index (3.784+/-0.533 vs 2.957+/-0.301 %, P<0.01), total serum cholesterol (1.60+/-0.41 vs 1.27+/-0.17 mmol/L,P<0.05) and free fatty acids (728.2+/-178.5 vs 429.2+/-96.7 mmol/L, P<0.01), serum alanine aminotransferase (1,257.51+/-671.34 vs 671.34+/-118.57 nkat/L, P<0.05) and aspartic aminotransferase (2,760.51+/-998.66 vs 1,648.29+/-414.16 nkat/L, P<0.01) were significantly increased in the NASH group. Whereas, when rats were fed on LCD protocol, their body weight (329.5+/-38.4 g, P<0.01), abdominal adipose content (310.21+/-1.52 g, P<0.05), liver index (3.199+/-0.552 %, P<0.05), and serum alanine aminotransferase (683.03+/-245.49 nkat/L, P<0.05) were significantly decreased, and the degree of hepatic steatosis (P<0.05) was markedly improved compared with those in the NASH group. However, no significant difference was found in serum lipid variables and hepatic inflammatory changes between the two groups. CONCLUSION: LCD might play a role in the prevention and treatment of obesity and hepatic steatosis in SD rats, but it exerts no significant effects on both serum lipid disorders and hepatic inflammatory changes.