Molecular responses of continuous and intermitent swimming and of exogenous melatonin in rats: cell signalizers of the intermediary metabolism and from the inflammatory and oxidative stress pathways

Abstract

Animal models are strictly important for the advance of scientific knowledge and, after two decades of research, our group has mastered the performance evaluation and physical training of rats and mices by the standardization of several protocols of aerobic and anaerobic capacity assessment. Recently, we developed an apparatus of tethered swimming and hydrostatic weighing to determine the propulsion force directly and to individualize the effort intensity by the body density respectively. Furthermore, in the physical training field we investigated the effects of systematic training and models of periodization. With the knowledge and tools acquired over the years, now we enabled the possibility of investigating the cellular mechanisms involved in the lactate metabolism, oxidative stress and inflammatory responses under extremely controlled effort intensity situations. Moreover, we will investigate experimental designs that ensure adequate chronobiological and environmental luminosity conditions by providing wakefulness in the night period to preserve the biological characteristics of the rat. In this context, this study will address: 1) the continuous and intermittent effort effects on protein content and gene expression of MCTs 1 and 4, PGC-1alpha and HIF-1alpha of skeletal muscle fibers type I and II; 2) the melatonin administration responses associated to continuous swimming exercise at maximal aerobic capacity on IKK/NF-kB pathway activity, at absolutely controlled situations from the circadian and effort intensity viewpoint, allowing a better understanding of these variables interaction with inflammatory system and oxidative stress. Our hypothesis is that the effort types proposed alter the expression of proteins of the intermediate metabolism differently and that the exogenous melatonin decreases the inflammatory and oxidative stress responses. (AU)