Decrease in Muscle Mass in Diet-Induced Visceral Obesity in Male Wistar Rats: Relationship with Hormonal and Metabolic Parameters

Decrease in muscle mass, as a rule, develops with the aging of the body, but in obesity the signs of decrease in mass and functional activity of the skeletal muscles are also registered, which requires experimental research. The aim of the work was to study the effect of diet-induced obesity and health variants of its correction on mass-metric and metabolic tissue parameters of musculus triceps surae in male Wistar rats. The experiments were carried out on sexually mature male Wistar rats and included the study of mass-metric, metabolic and hormonal indices characterizing the state of muscle tissue under the standard (Std, 16 weeks) and high-caloric diet (HCD, 16 weeks), during the transition from HCD to standard diet (HCD/StD, 8/8 weeks), when physical activity in the form of running on a treadmill was added (StD + running, HCD + running and HCD/StD + running, 8/8). Prolonged high-caloric diet led to the development of visceral obesity and decreased musculus triceps surae mass in male Wistar rats. Metabolic shifts were registered in the skeletal muscles during HCD, such as an increase in glucose, lactate, lactate dehydrogenase activity, and lipid peroxidation. Visceral obesity was accompanied by a decrease in serum testosterone content, but the concentration of the hormone in muscle tissue remained relatively stable. Application of moderate physical activity in HCD did not lead to correction of visceral fat mass, did not prevent decrease in muscle mass, but caused normalization of biochemical indices in muscle tissue and serum testosterone level. The most adequate correction of visceral obesity, muscle mass and biochemical indices in muscle tissue in male rats was achieved by switching from a high-caloric to a balanced diet regardless of physical activity. Thus, correction of diet-induced visceral obesity, muscle mass and associated metabolic shifts in male Wistar rats requires a transition to a balanced diet.