Alternatively activated M2 macrophages increase in early stages of experimental autoimmune myocarditis in Lewis rats / 대한수의학회지

To better understand the role of macrophages in early stages of experimental autoimmune myocarditis (EAM), we compared the expression of inducible nitric oxide synthase (iNOS) and arginase-1, markers for classically activated M1 and alternatively activated M2 macrophages, respectively, in the hearts of EAM-affected and control rats. Immunohistochemical evidence revealed that both iNOS-positive and arginase 1-positive macrophages were found in EAM lesions, while some cells were co-localized with both markers. This finding suggests that the increased level of arginase-1, which is partly from M2 macrophages, contributes to the modulation of EAM, possibly through the reduction of nitric oxide in the lesion.