MMP9 and Cerebral ischemia: To confirm whether functional recovery after transplantation of microglia preconditioned by OGD was associated with upregulation of VEGF, MMP-9, and TGF-β in the injured brain parenchyma, we performed immunohistochemical analyses of the brains of transplanted rats using antibodies against VEGF, MMP-9, and TGF-β at 28 days after cerebral ischemia.