Among them, MG6 cells expressed high levels of Cxcr2, S100a8, interleukin (IL)‐1β, and matrix metallopeptidase 9 (MMP9), demonstrating a unique “neutrophil‐like” phenotype and were considered to represent a stroke‐specific state of microglia in the aged brain after stroke. This evidence concerns the gene MMP9 and Stroke.