Investigação do efeito do treinamento de força e da suplementação com a proteína do soro do leite na nocicepção induzida por lesão muscular em ratos

Abstract

Muscle lesion accounts for about 55% for all causes of sports related injuries. The pain is one of the main symptoms during muscle lesion. Pain modulation during muscle lesion is complex and involves several mecanisms including the participation of glial cells mainly the microglias and astrocites. Strenght training and whey protein supplementation has been used as an alternative treatment for muscle lesion. However, the effect of strenght training and whey protein supplementation over the glial cells activation is unknown. The aim of this study was to investigate the nociceptive responses and the glial activation during muscle injury as well as the effectiveness of the strength training and whey protein supplementation as a treatment. The experiments were conducted on male Wistar rats, weighting around 250g and 300g. The muscle injury was induced using a mass drop contusion model. Then, the animals were submited to a two weeks long treatment, with strength training (3 times a week) and whey protein supplementation (daily). During the treatment, it was assessed the paw withdraw treshold, the temperature on the injury site, the gait paternns and the number of inflammatory cells. A pharmacological test was conducted in order to evaluate the participation of glial cells on the central modulation of the nociception. Using a Western Blot assay it was investigated the expression of microglias (Iba-1) and astrocites (GFAP). The results indicated that both the stregth training and the whey protein supplementation were effective on reducing the hiperalgesia and the number of inflamatory cells. Furthermore, the stregth training showed a significant improvement on the gait patterns. The pharmacological test showed that the glial cells participate on the pain modulation centrally. Most importantly, the western blot assay indicated that there is an increased expression of activated glial cells after muscle lesion, and that microglial activation was similar to the control group after the stregth training treatment. In conclusion, the strength training and the whey protein supplementation demonstrated some positive effects on the nociceptive responses, inflamatory responses and microglial activation.