Adaptive reactions of rats after light desynchronosis and physical overwork

It is known that desynchronosis and physical stress to the point of fatigue are powerful stressors for the body. Studies indicate a depleting effect of the combined stress factors on the adaptive reserves of the organism, especially when the joint exposure is prolonged. However, the adaptive value of the training process in various activities is also well known. In this regard, it seems important to study these two aspects of adaptation when combined effects of light desynchronosis and physical overwork on the body.Рurpose of this study was to study the features of adaptive reactions of rats under conditions of light desynchronosis and physical overwork.Materials and methods. An experimental study was performed on 60 mature male rats of the Wistar breed. For the induction of experimental desynchronosis, the animals of the experimental groups were kept for 10 days in artificial bright illumination (150 LX) or full darkening (2-3 LX). The model of physical overfatigue used the method of forced swimming of rats to complete fatigue in their own modification. At the end of the swim test, all the animals were withdrawn from the experiment and underwent one-step-long decapitation under CO2 with anesthesia. In decapitated animals, to collect serum, the blood was collected in a clean, dry vial. In the blood serum of rats, the biochemical standard method was used to determine the level of lactate. Using the ELISA method and the reagent kit “IBL” (Germany), the concentrations of corticosterone and serotonin were determined. The histological analysis of the stress-realizing organs was carried out according to a standard procedure using light microscopy using the Axioskop 40 microscope from CarlZeiss (Germany).Results. It was found that physical fatigue in rats after daily swimming activities (5 days) was accompanied by a decrease in the level of corticosterone in the blood serum and destructive changes in the adrenal and femoral muscles in comparison with intact animals. In comparison with the intact group, dark deprivation and physical activity did not alter the content of corticosterone, serotonin, and lactate in the blood and caused minor destructive processes in the adrenal glands. Light deprivation and fatigue lowered the level of corticosterone in the blood, caused destructive changes in the adrenal glands and muscles, and increased serotonin levels in serum, but did not change the level of lactate.Conclusions. The features of adaptive reactions of rats under conditions of light desynchronosis and physical overfatigue are determined by the nature of deprivation or the direction of the phase shift (deprivation of light or darkness). Dark deprivation followed by physical overfatigue causes the development of the resistance phase of the general adaptation syndrome, and light deprivation followed by physical overwork is the phase of exhaustion.