2‐Ethylhexyl Diphenyl Phosphate Inhibited C2C12 Myoblast Differentiation by Regulating ACTC1

ABSTRACT2‐ethylhexyl diphenyl phosphate (EHDPHP), a ubiquitous organic phosphorus flame retardant, is extensively employed in food packaging, flame retardancy applications, and other industrial processes as a crucial chemical. However, recent discoveries have underscored its diverse toxic effects, posing a severe potential threat to biological health. Skeletal muscle, vital for locomotion, relies heavily on proper differentiation during development and maintenance for strength and functionality. This study investigated the impact of EHDPHP on skeletal muscle differentiation by culturing C2C12 cells with varying concentrations of EHDPHP during induction of differentiation, as well as constructing a mouse muscle injury repair model through oral administration of 30 μg/kg EHDPHP for 7 weeks. Exposure to EHDPHP was found to impede skeletal muscle differentiation in mice. Utilizing techniques such as western blot analysis, RNA‐seq, and qRT‐PCR, our preliminary analysis revealed that low concentrations of EHDPHP inhibited the expression of ACTC1, subsequently suppressing MyoG and MYH2 expression levels, thereby hindering C2C12 myoblast differentiation. Furthermore, EHDPHP exposure disrupted the repair process of muscle injury in mice and compromised the integrity of the repaired tissue. In conclusion, these findings elucidate the detrimental effects of EHDPHP exposure on muscle differentiation, uncovering its muscle toxicity.