The Effects of Morning Versus Evening Aerobic Exercise Training on Proteins Associated with Browning of Visceral Adipose Tissue in a Diabetic Mouse Model

Introduction: Converting white adipose tissue to brown-like fat (browning) has shown promise in reducing diabetes-associated complications. This study aimed to determine the effect of aerobic exercise training time on CPT1, CLOCK, and irisin protein levels in diabetic mice. Methods: In this experimental study, 18 male NMRI mice (8-10 weeks old, mean weight 26 ± 2.23 g) were randomized into six groups (five animals/group): Healthy controls (light and dark phases), diabetic controls (light and dark phases), and diabetic exercise intervention groups (light and dark phases). Moderate-intensity aerobic exercise (50-60% of maximum running speed) was performed for eight weeks. Differences among experimental groups were statistically analyzed using two-way ANOVA, followed by Tukey’s HSD test. Results: Significantly elevated levels of CPT1, CLOCK, and irisin were observed in the healthy control group compared to the diabetic control group (P = 0.0001). In the dark-phase diabetic exercise training group, CPT1 (P = 0.001), CLOCK (P = 0.001), and irisin (P = 0.001) protein levels were significantly elevated compared to the diabetic control group. However, morning exercise training did not show a significant difference compared to the diabetic control group (P > 0.05). Conclusion: In this animal model, our results indicate that aerobic exercise undertaken during the dark phase could positively influence adipose tissue metabolism in diabetic conditions.