Mitochondrial Bioenergetic Remodeling in Type 2 Diabetes: A Comparative Analysis of the Effects of Continuous and Interval Aerobic Training on the Mitochondrial Biogenesis Axis (PGC-1α/TFAM) and Mitochondrial Fusion–Fission Homeostasis (MFN1/DRP1) in the Skeletal Muscle of Diabetic Rats
Keywords:
Type 2 Diabetes, Continuous Aerobic Training, Interval Aerobic Training, PGC-1α, TFAM, MFN1, DRP1, Skeletal MuscleAbstract
Mitochondrial dysfunction in type 2 diabetes is one of the major mechanisms underlying the reduced metabolic capacity of skeletal muscle. The present study was conducted to compare the effects of continuous and interval aerobic training on the mitochondrial biogenesis axis, including PGC-1α and TFAM, and on the mitochondrial fusion–fission balance, including MFN1 and DRP1, in the gastrocnemius muscle of diabetic rats. In this experimental study, male Wistar rats were assigned, following environmental acclimatization, to six groups: healthy control, healthy + continuous training, healthy + interval training, diabetic control, diabetic + continuous training, and diabetic + interval training (n = 8 per group). Diabetes was induced through a high-fat diet and intraperitoneal injection of streptozotocin. The exercise protocols were performed for eight weeks, five sessions per week. At the end of the intervention, the gastrocnemius muscle was harvested, and the relative expression levels of PGC-1α, TFAM, MFN1, and DRP1 genes were assessed using quantitative real-time polymerase chain reaction (qRT-PCR) and analyzed using the 2^−ΔΔCt method. Type 2 diabetes was associated with decreased expression of PGC-1α, TFAM, and MFN1 and increased expression of DRP1. Both exercise interventions improved mitochondrial indices. Interval training produced a more pronounced increase in PGC-1α and TFAM expression, whereas continuous training demonstrated a more distinct effect on modulating the MFN1 and DRP1 expression profile. The findings suggest that the structure of exercise intensity may activate different pathways of mitochondrial adaptation in diabetic skeletal muscle. Nevertheless, due to the animal-based nature of the study and the absence of certain technical qRT-PCR details in the initial version, the practical interpretation of the findings should be approached with caution and following completion of the methodological reporting.
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