Various conventional treatment strategies for volumetric muscle loss (VML) are often hampered by the extreme donor site morbidity, the limited availability of quality muscle flaps, and complicated, as well as invasive surgical procedures. The conventional biomaterial-based scaffolding systems carrying myoblasts have been extensively investigated towards improving the regeneration of the injured muscle tissues, as well as their injectable forms. However, the applicability of such designed systems has been restricted due to the lack of available vascular networks. Considering these facts, here we present the development of a unique set of two minimally invasively injectable modular microtissues, consisting of mouse myoblast (C2C12)-laden poly(lactic-co-glycolic acid) porous microspheres (PLGA PMs), or the micro-muscles, and human umbilical vein endothelial cell (HUVEC)-laden poly(ethylene glycol) hollow microrods (PEG HMs), or the microvessels. Besides systematic in vitro investigations, the myogenic performance of these modular composite microtissues, when co-injected, was explored in vivo using a mouse VML model, which confirmed improved in situ muscle regeneration and remolding. Together, we believe that the construction of these injectable modular microtissues and their combination for minimally invasive therapy provides a promising method for in situ tissue healing.

体积肌肉损失 (VML) 的各种传统治疗策略通常受到供体部位发病率极高、优质肌瓣的可用性有限以及复杂的侵入性外科手术的阻碍。携带成肌细胞的传统基于生物材料的支架系统已被广泛研究，以改善受伤肌肉组织的再生，以及它们的可注射形式。然而，由于缺乏可用的血管网络，这种设计系统的适用性受到限制。考虑到这些因素，在这里我们提出一个独特的组两个微创注射的模块化微组织的发展，包括小鼠成肌细胞的（C2C12）-laden聚（乳酸-共-乙醇酸）多孔微球（PLGA PM），或微肌肉，以及载有人脐静脉内皮细胞（HUVEC）的聚（乙二醇）空心微棒（PEG HMs），或微血管。除了系统的体外研究外，还使用小鼠 VML 模型在体内探索了这些模块化复合微组织的生肌性能，这证实了原位肌肉再生和重塑的改善。总之，我们相信这些可注射模块化微组织的构建及其用于微创治疗的组合为原位组织愈合提供了一种有前途的方法。