[Protective effect of anthocyanins on apoptosis of gastrocnemius muscle myocytes of rats after intense exercise]

Abstract

Currently, in sports medicine, much attention is paid to the prevention and treatment of delayed muscle soreness syndrome (DOMS), which occurs several hours or days after unusual or intense physical activity, as well as the state of athlete overtraining. One of the main pathogenetic factors in the development of this syndrome is myocyte ultrastructural damage with apoptosis activation. Therefore, using natural antioxidants in sports nutrition for the relief of this pathology is of particular relevance. The aim of the study was to study the effect of an anthocyanin-enriched diet on apoptosis of gastrocnemius muscle myocytes of rats after intense exercise. Material and methods. The experiment was carried out for 4 weeks on 4 groups of male Wistar rats (12 animals in each, initial body weight ~300 g). Animals were divided into groups of rats (groups 1 and 2), whose motor activity was limited by standard conditions for keeping animals in vivarium, and groups of physically active rats (groups 3 and 4), which received additional physical activity - treadmill training. Before the end of the experiment, the animals of groups 3 and 4 were given debilitating (until the rats refused to continue the exercise) physical activity on a treadmill. Rats of all four groups received a standard semi-synthetic diet, water ad libitum. Animals in groups 2 and 4 were additionally given blueberry and blackcurrant extract (30% anthocyanins) as part of the diet at a daily dose of 15 mg anthocyanins/kg body weight. The intensity of apoptosis of gastrocnemius muscle myocytes was studied by flow cytometry. Cells were stained with fluorochrome-conjugated annexin V and vital dye 7-aminoactinomycin. The results are presented as the percentage of intact cells and cells at different stages of apoptosis per 100 000 counted objects in each sample. Results. The enrichment of the diet of control group rats with blueberry and black currant extract did not have a significant effect on the relative content of intact cells and the studied parameters of apoptosis of gastrocnemius muscle myocytes of rats of the 2nd group. Intense physical activity in rats of the 3rd group led to a statistically significant (p<0.05) decrease in the relative content of intact (live) cells compared with this indicator in rats of other groups (85.32±1.44 vs 90.87±0.66% - in the 1st group; 90.16±0.79% - in the 2nd group; 89.01±0.81% - in the 4th group, р<0.05). After intense physical activity in rats of the 3rd group, activation of apoptosis of gastrocnemius muscle myocytes was found, as evidenced by an increase in the relative content of objects in apoptosis compared with other groups (11.61±1.45 vs 7.88±0.60% - in the 1st group, р<0.05; 8.01±0.70% - in the 2nd group, p<0.10; 7.93±0.59% - in the 4th group р<0.05). Enrichment of the diet of exercise rats with blueberry and blackcurrant extract (4th group) had a protective effect on the intensity of the apoptosis process, the studied parameters did not differ significantly from those in rats of the control and the 2nd groups. Conclusion. The results of the study indicate the activation of the process of apoptosis of gastrocnemius muscle myocytes of rats after intense physical activity. Enrichment of rats' diet with anthocyanins from blueberry and black currant extracts ensures the restoration of the studied apoptosis parameters to the level of control group rats. In the control group of rats with normal physical activity, the addition of anthocyanins to the diet does not have a significant effect on the physiological process of apoptosis of gastrocnemius muscle myocytes. In this way, an evidence base for the effectiveness of the use of biologically active substances - anthocyanins - in sports nutrition for the restoration of skeletal muscles has been obtained.

Keywords: anthocyanins; apoptosis; gastrocnemius muscle; physical activity; rats.