The environmental problem of Microplastics (MPs) pollution poses a great threat to human and animal health, which has attracted global attention. The physiological integrity of skeletal muscle is extremely important for the survival of animals. Here, we investigated the effect of two size polystyrene microplastics (PS-MPs, 1–10 µm and 50–100 µm) on the growth of anterior tibial (TA) muscle and repair after injury in mice. Results showed that the regeneration of skeletal muscle was delayed by PS-MPs exposure and was negatively correlated with particle size. H&E staining and Oil red O staining showed that PS-MPs exposure reduced the average cross-sectional area (CSA) and diameter of the muscle fibers, increased lipid deposition. Further mechanistic research displayed that though PS-MPs treatment did not affect cell viability of myoblast, it aggravated intracellular ROS generation and oxidative stress, inhibited myogenic differentiation by decreasing the phosphorylation of p38 MAPK, and promote adipogenic differentiation by increasing the expression of NF-κB, which could be alleviated by NAC. In brief, our data demonstrated that the ROS overproduction caused by PS-MPs disturbed the regeneration of skeletal muscle and directed the fate of satellite cells in mice.

微塑料（MPs）污染的环境问题对人类和动物健康构成了巨大威胁，引起了全球关注。骨骼肌的生理完整性对于动物的生存极为重要。在这里，我们研究了两种尺寸的聚苯乙烯微塑料（PS-MP，1–10 µm和50–100 µm）对小鼠前胫骨（TA）肌肉生长和损伤后修复的影响。结果表明，骨骼肌的再生被PS-MPs暴露所延迟，并且与粒径呈负相关。H＆E染色和油红O染色显示PS-MPs暴露会降低平均横截面积（CSA）和肌肉纤维直径，从而增加脂质沉积。进一步的机理研究表明，尽管PS-MPs处理不会影响成肌细胞的细胞活力，它可以增加细胞内ROS的产生和氧化应激，通过减少p38 MAPK的磷酸化抑制成肌分化，并通过增加NF-κB的表达促进成脂分化，这可以被NAC缓解。简而言之，我们的数据表明，由PS-MP引起的ROS过度生产干扰了骨骼肌的再生，并控制了小鼠卫星细胞的命运。