Effects of MICT and HIIT on mitochondrial dynamics-related proteins in visceral adipose tissue of type 2 diabetic rats.

BACKGROUND

Adipose tissue, as an endocrine gland, significantly influences the pathophysiology of type 2 diabetes (T2DM) through mitochondrial dysfunction. This study examined the effects of two exercise training types on mitochondrial dynamic protein content in visceral adipose tissue (VAT) of T2DM-induced rats.

METHODS

Male Wistar rats (total n = 40; 8–10 weeks old, ~ 220 g) were used. Thirty-two rats were fed a high-fat diet (HFD) for 6 weeks and received streptozotocin (STZ) to induce type 2 diabetes mellitus (T2DM). Eight additional rats were maintained on standard chow as the healthy control group (NC, n = 8). The diabetic rats were randomly divided into three groups (n = 8 each): diabetic control (DC), diabetes + MICT (MICT + D), and diabetes + HIIT (HIIT + D). All animals (total n = 40) completed the study and were included in the analyses. MICT involved 8 weeks of training (5 sessions/week, 50 min at 60% maximal speed), while HIIT consisted of 8 weeks (5 sessions/week, 4–7 sets of 4 min at 80–90% maximal speed). Western blot analysis revealed significant increases in mitochondrial fission proteins (Drp-1: 238%, Fis-1: 99%) in the DC group compared to HC (p < 0.05).

RESULTS

Both MICT and HIIT significantly reduced Drp-1 (53.55%, 77.81%) and Fis-1 (16.08%, 36.18%) while increasing MFN-2 (26.25%, 57.50%) and OPA-1 (66.10%, 103.39%) compared to DC. HIIT showed greater changes than MICT (p < 0.05). Additionally, fasting serum glucose and HOMA-IR levels were significantly lower in both exercise groups (p < 0.001).

CONCLUSIONS

In conclusion, Type 2 diabetes causes changes in the levels of proteins regulating mitochondrial fission and fusion in visceral adipose tissue, which can be improved through MICT and HIIT training, potentially increasing aerobic capacity and glucose metabolism.