Nutritional hepatic steatosis and mortality after burn injury in rats

Aims: To investigate the effects of diet composition and starvation on hepatic steatosis and mortality after severe burn injury in rats. Methods: Experiment 1: rats received either normal chow (55% of energy carbohydrates, 14% fat, 31% protein), a high-fat (40% carbohydrates, 40% fat, 20% protein), or a high-carbohydrate diet (81% carbohydrates, 4% fat, 15% protein) ad libitum for 6 days. Another three groups received these diets ad libitum for 6 days after 48 h starvation. Experiment 2: mortality after 60% total body surface area scald burn was determined in a control group of rats and a group with nutritionally induced hepatic steatosis. Hepatic steatosis was induced by feeding the rats a high-fat diet (40% carbohydrates, 4% fat, 15% protein) ad libitum for 6 days. Results: Without starvation, liver triglyceride content (mg/g liver) increased in response to the high-fat diet (25.6±6.9) compared to normal chow (9.4±3.8; P< 0.05); the high-carbohydrate diet had no influence on liver triglyceride content (12.4±3.7). Refeeding after starvation resulted in elevated (P< 0.05) liver triglyceride content in the high-fat (18.8±8.3) and the high-carbohydrate group (28.7±14.4 vs control 6.7±3.7). Liver triglyceride content correlated (R2=0.72; P< 0.05) to non-protein energy intake but not to total energy intake. Burn caused 33% mortality in the hepatic steatosis group and no deaths in the control group (P< 0.05). Conclusions: Diet composition and preceeding starvation independently manipulate hepatic fat content in rats. Hepatic steatosis increases mortality after burn injury. Thus, nutritional interventions to reduce hepatic fat accumulation may be beneficial.