Exposure to melamine cyanuric acid in adult mice caused motor activity and skeletal muscle energy metabolism disorder

•MCA exposure interfered with endocrine homeostasis in adult mice.•MCA exposure caused behavior disorder induced open field test in adult mice.•MCA exposure interfered with the expression of skeletal muscle thermogenic and morphogenic genes.•Exposure to MCA caused histomorphological changes in skeletal muscle in adult mice.•MCA exposure caused abnormal skeletal muscle energy metabolism. Thyroid hormone has a variety of physiological functions and plays an important role in the development of central nervous system, skeletal muscle and lung, as well as body temperature regulation. Skeletal muscle is a key determinant of basal metabolic rate and systemic energy metabolism. It contains Myopsin (SLN) which plays an important role in muscle heat production and energy metabolism. Melamine cyanuric acid (MCA) is an important component of the new flame retardant, but also a chemical interfering substance that can affect the endocrine in the body. It is mainly distributed in nylon and other flame retardant substances. Therefore, in this study, male mice were exposed to MCA at 10, 20 and 30 mg/kg for four weeks. We explored the effects of MCA exposure on skeletal muscle morphology, thermogenic gene expression and motor activity to explore whether MCA exposure could induce skeletal muscle hyperthermia and energy metabolism disorders and its underlying mechanisms. The results showed that the motor activity of male mice exposed to MCA was decreased, the morphology of skeletal muscle tissue was impaired, and the levels of morphological and thermogenic genes in skeletal muscle were destroyed. These findings are intended to provide a preliminary reference for studying the effects of MCA exposure on thermogenesis and energy metabolism in adult mice.