CoQ10-Supported HIIT Modulates Skeletal Muscle and Hippocampal Biomarkers in Rats: A Randomized, Repeated-Measures, Post-Test Controlled Design

This study examined how coenzyme Q10-supported high-intensity interval training (HIIT) influences plasma lactate threshold, skeletal muscle oxidative capacity, circulating irisin and corticosterone, and hippocampal brain-derived neurotrophic factor (BDNF) and glial fibrillary acidic protein (GFAP) levels in rats. Forty-eight male Sprague Dawley rats (8 weeks old; 250.4 ± 11.2 g) were randomized into four groups: control (C), coenzyme Q10 (Supp), HIIT, and HIIT with coenzyme Q10 (HIITsupp). HIIT was performed five days per week on a treadmill following a four-stage familiarization. Coenzyme Q10 (5 mg/kg/day) was given by gavage 30 min before HIIT during weeks II-IV. Plasma lactate threshold, corticosterone, irisin, and citrate synthase (CS) activity were measured by ELISA, while hippocampal BDNF and GFAP were analyzed by both ELISA and immunohistochemistry. The HIITsupp group showed greater muscle mass, CS activity, plasma irisin, and hippocampal BDNF, along with lower GFAP and lactate threshold than the C, Supp, and HIIT groups. The Supp group had the lowest corticosterone, while the HIIT group maintained the highest lactate threshold before supplementation. Principal Component Analysis (PCA) indicated distinct clustering, with the C group closely associated with GFAP and corticosterone, whereas the HIITsupp group aligned with oxidative and neurotrophic markers. Coenzyme Q10-supported HIIT improved muscle oxidative capacity, lowered lactate, and modulated corticosterone, GFAP, and hippocampal BDNF, indicating integrated metabolic and neurobiological adaptations.