丝胶生物支架负载基因工程成肌细胞在骨骼肌严重缺损修复中的应用及机制研究

创伤导致的严重骨骼肌缺损(Volumetric muscle loss，VML)是临床常见的致残性疾病，其结构和功能修复是目前亟待解决的医学难题。组织工程生物支架能为种子细胞长期存活提供良好微环境，然而损伤部位过度纤维化往往限制其修复效果。我们前期研究证明丝胶具有促血管生成和促神经生长作用；发现富载miR29的细胞外囊泡(miR29-EVs)能诱导成肌细胞定向分化为肌管；并初步发现在心脏毒素(cardiotoxin，CTX)引起的骨骼肌损伤动物模型中，植入搭载miR29-EVs预处理成肌细胞的丝胶生物支架，可促进成肌细胞与宿主有效融合并抑制纤维化，改善骨胳肌结构和功能。本项目拟研发一种适用于骨胳肌VML修复的丝胶生物支架，并与上述治疗要素联用，在小鼠损伤模型中综合评价此策略修复效果，并采用RNA-seq技术结合生物信息学分析探索再生修复关键基因及分子机制，为骨骼肌创伤修复提供新方法。

Volumetric muscle loss (VML) injury is a common type of severe injury that usually leads to disabilities in clinical practice. However, functional and structural recovery of VML still remains challenging. Tissue engineered scaffolds can provide favorable microenvironment suitable for long-term survival of transplanted cells. However, the excessive fibrosis usually limits the repairing outcomes. Recently, we reported that sericin biomaterial has pro-angiogenesis activities and is also capable of promoting nerves growth. In this study, we found that miR29-enriched extracellular vesicles (miR29-EVs) promoted the differentiation of myoblasts into myotubes and inhibited fibrosis. Implantation of sericin scaffold carrying miR29-EVs-treated primary myoblasts significantly enhanced the integration of primary myoblasts and host muscle and effectively inhibited fibrosis in a cardiotoxin-induced severe mouse tibialis anterior (TA) muscle injury model. Moreover, functional and structural recovery of skeletal muscle was observed after implantation. We aim to develop a type of sericin scaffold suitable for skeletal muscle repair, and to examine its therapeutic effect when used in combination with other tissue engineering key components. We plan to comprehensively evaluate the therapeutic outcomes of this strategy in a mouse VML injury model, and utilizing RNA-seq techniques combined with bioinformatics analyses to find out key genes and the molecular mechanism involved in the regeneration process. We hope the implementation of this project may provide an alternative tissue engineering approach for the repair and treatment of VML in the future.