['Transplantation of bone marrow cells has been reported to exert neuroprotection against cerebral ischemia. However, the effect of bone marrow mononuclear cells (BMMCs) administered immediately after reperfusion has rarely been investigated. The present study was designed to examine whether brain injury in response to transient focal ischemia can be ameliorated by BMMC administration immediately after reperfusion in rats, and to determine whether there are differences in the route of administration.', 'Autologous BMMCs were obtained from each rat. Rats were then subjected to transient focal ischemia followed by BMMC administration via the ipsilateral carotid artery (IA group) or the femoral vein (IV group) immediately after reperfusion. Control rats underwent the same procedure but received vehicle injection. Infarct volume was compared among the groups 24 h and 7 days after reperfusion. BMMCs were fluorescently labeled with PKH26 prior to administration to track transplanted cells.', 'Total infarct volume decreased in the IA group, but not in the IV group, when compared to the vehicle group. In the ipsilateral hemisphere, PKH26 positive cell count was greater in the IA group than in the IV group. Motor function, assessed with a rotarod test, improved in the IA group compared to the vehicle group.'] Does intra-arterial transplantation of bone marrow mononuclear cells immediately after reperfusion decrease brain injury after focal ischemia in rats?