Pathomorphological Changes in the Liver and Expression of the tgfb1 Gene during Physical Activity and after Meldonium Administration in an Experiment in Rats.

Male Wistar rats were subjected to mild, moderate, and heavy physical exercises (10 swimming sessions), after which they were euthanized (immediately or 30 days after the last session). Animals of the experimental groups received meldonium (100-120 mg/kg of body weight) with food for 10 days of swimming. Heavy exercise led to the development of degeneration, necrotic patches, and cellular infiltration in the liver and a decrease of the TGF-β1 level. In 30 days after the last swimming session, an increase in both the level of TGF-β1 in the cytoplasmic fraction and the expression of the tgfb1 gene were observed. The level of TGF-β1 increased by 1.8 times against the background of meldonium treatment and decreased by 1.6 times in 30 days; tgfbl expression also decreased by 1.3 times in comparison with that in rats exposed to a similar exercise without meldonium (p < 0.05). The use of meldonium against the background of heavy physical exercise contributed to the achievement of gene expression and cytokine levels approaching the target values observed in intact animals and prevent severe alterative changes in the liver.