CD200+ and CD200− macrophages accumulated in ischemic lesions of rat brain: The two populations cannot be classified as either M1 or M2 macrophages

• Two types of macrophages were accumulated in the core lesion of ischemic rat brains.
• Highly proliferative NG2+/CD200−/CD200R+ macrophages did not express iNOS.
• NG2−/CD200+/CD200R+ macrophages expressed iNOS and proinflammatory cytokines.
• Yet, the two types of macrophage were not fully applicable to M1/M2 classification.
• CD200–CD200R interaction might affect properties of the two types.

Two types of macrophages in lesion core of rat stroke model were identified according to NG2 chondroitin sulfate proteoglycan (NG2) and CD200 expression. NG2+ macrophages were CD200−, and vice versa. NG2− macrophages expressed two splice variants of CD200 that are CD200L and CD200S. CD200+ macrophages expressed CD8, CD68, CD163, CCL2, inducible nitric oxide synthase, interleukin-1β, Toll-like receptor 4 and transforming growth factor β, whilst NG2+ cells expressed a costimulatory factor CD86. Both cell types expressed insulin-like growth factor 1 and CD200R. These results demonstrate that the two macrophage types cannot be classified as either M1 or M2.

Figure optionsDownload high-quality image (251 K)Download as PowerPoint slide