Promotion of liver steatosis in rats by high-fat and/or high protein diets

NU04

Leonardi, DS; Feres, MBC; Zanutto, ME; Portari, GV; Junior, AAJ

Curso de Nutrição e Metabolismo, Departamento de Clinica Médica, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo.

Introdution:  The hepatic steatosis is a macrovesicular fat accumulation, that represent a liver alteration. Studies with normal rats are showing they become obeses and growing hepatic steatosis when eat high fat diets ad libitum. When changes the diet composition, it can advance to promove hepatic steatosis and compromise the liver, so it’s very important to find out the diets action. Objective: We analyzed the effects of different kinds of diets in promotion of  liver steatosis in rats and the possible adverse effects in the lipid peroxidation and antioxidants levels, in correlation with the grade of steatosis. Methods: We used 30 male Wistar rats, divided in 3 groups: Control Diet AIN-93; High Fat Diet with 50% of satured fat and High Fat and Protein Diet with 50% of satured fat and 40% of protein. In the begin the  animals had diet adaptation period, after this, each group received the diets and water ad libitum during 28 days. The animals were killed after the 28 days of diet, we collected the liver and blood to biochemical assays: Vitamin E, GSH, TBARS and Glucose. The grade of hepatic steatosis was assayed by histological analyses and by total liver fat. Results: Concerning the average intake of the diet at the first and the last weeks, there was no statistical differences between the three groups (p>0,05). The medium weight of the liver of the rats was significant different between the three groups (p<0,05). The glycemic levels of the group HPLS were significant higher than the others (p<0,05). The average liver fat levels of the groups HPLS e HLS were significant higher comparing with the control group, and, the medium value of  HPLS was significantly higher than the HLS, too. The total hepatic MDA value of the HPLS group was significantly higher. However, the free hepatic MDA medium value and the vitamin E medium value of the control group were significantly higher than the HLS group, which were significantly higher than the HPLS group. The GSH value of the control group was significantly higher than the HLS group. The histologic analysis of the liver show absense of hepatic steatosis in control group, mild steatosis for the HLS group and for the HPLS group the level of steatosis vary between mild, moderate and severe. Conclusion:  We showed through this study that high fat diet can increase hepatic steatosis, while the other diet, high fat and protein is worse than high fat diet only, because we found more hepatic steatosis and disbalance in oxidative stress.