The effects of eight-week treadmill exercise on adipocyte differentiation and insulin sensitivity in high-fat diet rat

Objective: To study the effects of aerobic exercise on insulin resistence in the rats feed by high-fat-diet and discuss whether the effect acted via the adipocyte differentiation. Method: Forty male SD rats were randomly assigned to four groups: control(C), high-fat diet control(H), high-fat diet control+exercise training(HE) and exercise training(E) group. Rats in HE and E groups were given treadmill exercise training. Insulin sensitivity and adipocyte parameters were evaluated. Result: The insulin resistence rat model was duplicated successfully by high-fat-diet. The changes of adipose differentiation were as follows: PPAR γ protein of E group was higher than that of C group(P < 0.01); that of H group was higher than C group, that of HE group was lower than H group. C/EBP α protein of H group was higher than that of other groups(P < 0.01); that of E group was higher than C group, that of HE group was lower than H group. The adipose differentiation of E group was the highest compared with C and H groups(P < 0.01); the proliferation index of C group was the highest compared with H and E groups(P < 0.01 and P < 0.05), that of HE group was lower than H and E groups(P < 0.05). In E group size of adipose cells was smaller than that of C group(P < 0.01), number of cells were more than that of C group; in H group size of adipose cells was smaller than that of C group (P < 0.01), and the number increased (P < 0.01); in HE group size of adipose cells was larger than that of G group(P < 0.01) and the number decreased. There was correlation between adipocyte differentiation and insulin resistance. Conclusion: Treadmill exercise for 8 weeks could improve the insulin resistence induced by high-fat diet and the inner mechanism may be related to adipose differentiation.