Effects of Swimming Training on Immune Function of Growing Rats Fed a High-Fat Diet

Abstract

The effects of swimming exercise on immune function of growing rats fed a high-fat diet were studied. Thirty-four male rats were randomly divided into 4 groups: CS (control diet sedentary group, n=8), CE (control diet exercised group, n=9), HS (high-fat diet sedentary group, n=8) and HE (high-fat diet exercised group, n=9). The high-fat diet was included 35% carbohydrate, 20% protein and 35% fat. AIN-76 was used as the control diet. In the exercised groups, the rats swam for 60 min day−1, 5 days/week for 4 weeks. Mean blood glucose, total cholesterol, and triglyceride levels were not significantly different between groups, and neither were mean soleus muscle mitochondrial citrate synthase activities. However, the CD4+/CD8+ ratio (p<0.05) and the glycogen content of the plantarius muscle were significantly lower in the HS group than in the CS group. The CD4+ T cell population of the spleen and the glycogen content of the plantarius muscle were significantly higher in the HE group than in the HS group (p<0.01 and p<0.05 respectively). Interleukin-2 production following 5 µg/ml of conconavalin A (Con. A) stimulation tended to be higher in the HE group than in the other groups but the difference was not statistically significant. It is suggested that regular endurance exercise in growing rats fed a high-fat diet increases the CD4+ T cell subpopulation by stimulating interleukin-2 production.