Chronic Melatonin Administration On Muscle FATCD36 And Triacylglycerol After 12-wk Endurance Training Under Hypoestrogenism

All female organisms will perceive hypoestrogenism in certain life stage, leading to fat disturbances and health consequences. Endurance training is a valuable tool and recently the melatonin (Mel) administration has emerged with potential to improve skeletal muscle health. Despite some data showing positive Mel effects on muscle, it is unclear if its chronic administration can mimic or potentialize the training effect on fatty acid translocase CD36 (FATCD36) and triacylglycerol (TG) content. PURPOSE: To determine the impact of Mel administration on FATCD36 and TG after 12-wk endurance training under hypoestrogenism. METHODS: The study was previously approved by Institutional Animal Use Committee (1694190521). Forty female Wistar rats were subjected to a bilateral ovariectomy (fifteenth week of age). Then, during 12-wk, Mel (10 mg.kg.day-1, via gavage) or vehicle solution was administered. It was also performed five days a week swimming endurance training (30 min.day-1 at 80% of individually determined maximal aerobic capacity). Four groups were formed: Control (C), Mel (M), trained (T) and trained with Mel (TM). Muscle triacylglycerol (TG) was determined through commercial kit and FATCD36 expression through immunofluorescence method. Data were expressed in mean ± EPM and Anova two-way with Newmann-Keuls post hoc were used under P < 0.05. RESULTS: Mel and training Anova main effects were found for FATCD36 (F > 21,6; P < 0.001) but only the significative effect of training was found for TG (F = 14,66; P < 0.001). Interaction was found between main effects for FATCD36 (F = 7,49; P < 0.01). Data of FATCD36 and TG are illustrated at figure 1. CONCLUSION: Chronic Mel administration increased FATCD36 under hypoestrogenism, but was only effective in helping regulate muscle TG if combined with training. Supported by: São Paulo Research Fundation, FAPESP, 2021/03951-2