Adult male Sprague-Dawley rats were subjected to right middle cerebral artery occlusion for 60 minutes. During the 1-hour occlusion, animals were randomly assigned to 1 of the following treatments: intravenous injection of HUCB (a subtherapeutic dose of 200 000 cells in 10 μL) with blood–brain barrier (BBB) permeabilizer (1.1 mol/L mannitol at 4°C) or vehicle, intravenous vehicle alone, or intravenous mannitol alone. Behavioral tests, using elevated body swing test and passive avoidance test, were conducted at day 3 poststroke, and thereafter, animals were euthanized for: (1) immunohistochemical examination of HUCB, which were lentivirally labeled with green fluorescent protein; (2) cerebral infarction analysis using 2,3,5-triphenyl-tetrazolium chloride; and (3) enzyme-linked immunosorbent assay of trophic factors within the striatal region.