High-fat diet did not change metabolic response to acute stress in rats

This study investigated the effects of high-fat diet on metabolic factors in the presence of acute foot-shock and psychological stresses in male Wistar rats. The animals were divided into high-fat (45 % cow intra-abdominal fat) and normal (standard pellets) diet groups; then, each group was allocated into stressed and control groups. Stress was induced by a communication box. Blood samples were collected by retro-orbital-puncture method under isoflurane anesthesia. Plasma levels of glucose, insulin, triglyceride, cholesterol, free fatty acid and corticosterone were measured. Water and food intake significantly decreased in high-fat diet group; however, their weight did not change compared with the normal diet group. The level of fasting plasma glucose in the high-fat diet group decreased whereas, the fasting plasma insulin level did not significantly change. Stress increased the plasma glucose level 15 minutes after oral glucose tolerance test (OGTT) in both diet subgroups. The concentration of plasma insulin increased after stress induction in fasting and 15 minutes after performing OGTT. The increase in the plasma level of corticosterone was significant in both diet subgroups of only the foot-shock stress group. Plasma level of cholesterol and triglyceride in the high-fat diet group significantly increased; however, foot-shock stress decreased only triglyceride concentration. Plasma level of the fatty acids did not change in any of the groups. Statistical analysis showed no significant interaction between high-fat diet and stress. As a whole, the results showed that the high-fat diet used in the present study did not noticeably affect metabolic parameters even in the presence of acute stress.