INFLUÊNCIA DA COMBINAÇÃO ENTRE SUPLEMENTAÇÃO COM CREATINA E TREINAMENTO FÍSICO RESISTIDO SOBRE VIAS MOLECULARES HIPERTRÓFICAS NO MÚSCULO ESTRIADO DE RATOS SAUDÁVEIS

Abstract

INTRODUCTION: Creatine, a popular supplement among athletes and physically active individuals, is of increasing interest due to its effects in enhancing performance and muscle mass. However, the role of the association of creatine and resistance training in the regulation of protein synthesis and signaling of hypertrophic molecular pathways and expression of MyHC isoforms in skeletal and cardiac striated musculature is not clear. OBJECTIVE: To analyze the influence of the combination between creatine supplementation and resistance training on hypertrophic molecular pathways in the striated muscle of healthy rats. MATERIAL AND METHODS: Wistar rats (n=28) were divided into four groups: Control (Cc), Creatine (Cr), Resistance Training (Tc) and Resistance Training and Creatine (Tcr). The animals in the Cc and Tc groups were treated with standard commercial feed ad libitum, while the Cr and Tcr groups received the same commercial feed with an addition of 2% creatine monohydrate ad libitum. In addition, Tc and Tcr performed a resistance training protocol three times a week. After 12 weeks, the nutritional behavior, the functional capacity, the macroscopic and microscopic morphology of the striated musculature, the expression of proteins of the myostatin signaling pathway and the composition of myosin heavy chains of the striated musculature were analyzed. Variables were evaluated using Two-Way ANOVA, complemented with Tukey's test. 5% significance. RESULTS: In the gastrocnemius, resistance training increased muscle-to-body weight ratio, cross-sectional area, interstitial collagen fraction, as well as MyHC IIx and follistatin, while decreasing myostatin and ActRIIB expressions. In the soleus, training increased the fraction of interstitial collagen and follistatin. The myocardium was not affected by the interventions. CONCLUSION: Resistance training induces skeletal muscle hypertrophy, interstitial remodeling, modulates MyHC expression, more evidently in the gastrocnemius muscle and does not promote alterations in the cardiac muscle. Effects are not affected by creatine supplementation.