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The effect of treadmill training loads on the content of cytokines in mice skeletal muscles with metabolic disorders induced by a 16 week high fat diet (HFD) was studied. The study included accounting the age and biorhythmological aspects. In the experiment, mice were used at the age of 4 and 32 weeks, by the end of the experiment—respectively 20 and 48 weeks. HFD feeding lasted 16 weeks. Treadmill training were carried out for last 4 weeks six times a week, the duration 60 min and the speed from 15 to 18 m/min. Three modes of loading were applied. The first subgroup was subjected to stress in the morning hours (light phase); the second subgroup was subjected to stress in the evening hours (dark phase); the third subgroup was subjected to loads in the shift mode (the first- and third-weeks treadmill training was used in the morning hours, the second and fourth treadmill training was used in the evening hours). In 20-week-old animals, the exercise effect does not depend on the training regime, however, in 48-week-old animals, the decrease in body weight in mice with the shift training regime was more profound. HFD affected muscle myokine levels. The content of all myokines, except for LIF, decreased, while the concentration of CLCX1 decreased only in young animals in response to HFD. The treadmill training caused multidirectional changes in the concentration of myokines in muscle tissue. The IL-6 content changed most profoundly. These changes were observed in all groups of animals. The changes depended to the greatest extent on the training time scheme. The effect of physical activity on the content of IL-15 in the skeletal muscle tissue was observed mostly in 48-week-old mice. In 20-week-old animals, physical activity led to an increase in the concentration of LIF in muscle tissue when applied under the training during the dark phase or shift training scheme. In the HFD group, this effect was significantly more pronounced. The content of CXCL1 did not change with the use of treadmill training in almost all groups of animals. Physical activity, introduced considering circadian rhythms, is a promising way of influencing metabolic processes both at the cellular and systemic levels, which is important for the search for new ways of correcting metabolic disorders.

An experimental model of the obesity and type II diabetes mellitus formation in C57BL/6 mice using a high fat diet was developed and tested. In the study, it was shown that mice feeding high-fat diet had a significant body weight gain during the 3rd week. By the end of the experiment, body weight has more than doubled. In mice that feed chow diet, body weight increased by 50%, by the end of the experiment It was shown that high fat diet also induced glucose tolerance, and the insulin concentration tripled. The data obtained confirm the adequacy of the experimental model of diabetes mellitus type II in mice.

The effect of forced treadmill running on the level of some cytokines in skeletal muscles of mice with a model of type II diabetes mellitus was studied. The mouse model was developed using a 12-week high-fat diet; physical loading in the form of forced treadmill running was applied for 4 weeks. The concentration of myokines in m. gastrocnemius was determined by an enzyme-linked immunosorbent assay (ELISA). Diabetes formation in mice was accompanied by changes in the skeletal muscle concentration of two pro-inflammatory cytokines: an increase in IL-6 and a decrease in IL-15. Forced treadmill running loads had differential effects on the level of myokines in healthy and sick mice. In healthy animals, there was a decrease in IL-6 and IL-15 concentrations and an increase in the leukemia inhibitory factor (LIF) concentration in skeletal muscles after 4 weeks of regular forced running. At the same time, in diabetic mice, IL-6 and IL-15 concentrations increased, while the LIF concentration decreased after forced running loads. The NAP3 concentration in skeletal muscles was found to be insensitive to both the development of type II diabetes mellitus and regular forced treadmill running.