Zn-DHM Nanozymes Enhance Muscle Regeneration Through ROS Scavenging and Macrophage Polarization in Volumetric Muscle Loss Revealed by Single-Cell Profiling

Abstract

Volumetric muscle loss (VML) is a severe condition in which the loss of skeletal muscle surpasses the body's intrinsic repair capabilities, leading to irreversible functional deficits and potential disability, with persistent inflammation and impaired myogenic differentiation. To address these challenges, a novel zinc-dihydromyricetin (Zn-DHM) nanozyme with superoxide dismutase (SOD)-like activity is developed, designed to neutralize excessive reactive oxygen species (ROS) and restore oxidative balance. Zn-DHM mitigates oxidative stress and promotes polarization of macrophages from the proinflammatory M1 phenotype to the anti-inflammatory M2 phenotype, thereby reducing chronic inflammation and creating a conducive environment for muscle repair. Further, Zn-DHM significantly enhances the myogenic differentiation of C₂C₁₂ cells, accelerating wound healing processes. These studies confirm the biosafety and low toxicity of Zn-DHM. As per a murine tibialis anterior VML model, Zn-DHM effectively suppresses inflammation and markedly improves skeletal muscle repair outcomes. Single-cell RNA sequencing reveals that Zn-DHM treatment increases the expression of M2 macrophage markers and enhances the proliferation and differentiation capacity of muscle stem cells (MuSCs). In addition, intercellular communication analysis reveals interactions between MuSCs and macrophages in the Zn-DHM treatment group, suggesting that these interactions may drive tissue regeneration through the activation of the GAS and Notch signaling pathways.