Dipyrone attenuates microglia activation induced by focal cerebral ischemia in mouse. Dipyrone (100 ng) was administered by i.c.v. 30 minutes before the onset of MCAO. Mice were sacrificed 24 hours after MCAO, and brains were removed and fixed. 20-μm-thick coronal cryosections were prepared and immunostained with antibody to CD11b (dark stained, A) or Iba1 (green, B). Hematoxylin or DAPI (blue) staining was used as the counterstain, respectively. As phenotypic marker of microglia, the increased expression of CD11b or Iba1 corresponds to severity of microglial activation. Scale bars, 150 μm.