In vitro and in vivo Repair Activities of Undifferentiated and Classically and Alternatively Activated Macrophages

<b><i>Objective:</i></b> Macrophages play a critical role in wound repair. However, the specific role of the different macrophage subtypes in wound repair remains incompletely understood. The aim of this study was to compare the wound repair activities of undifferentiated macrophages (M0), classically activated macrophages (M1) and alternatively activated (M2) macrophages. <b><i>Methods:</i></b> The macrophage repair activities of intestinal wounds were evaluated using in vitro and in vivo models. <b><i>Results:</i></b> All three macrophage subtypes enhanced wound closure in vitro, with the M2 macrophages demonstrating greater repair activities than the M0 and M1 macrophages. Injection of M0 and M2 macrophages into mice with experimental dextran sodium sulfate-induced colitis significantly enhanced ulcer repair when compared to control mice. In contrast, injection of M1 macrophages did not affect ulcer repair. <b><i>Conclusions:</i></b> These results underscore the wound repair capacity of different macrophage subsets. Notably, wound repair activity is not restricted to M2 macrophages, as the current literature suggests.