Migration of enhanced green fluorescent protein labeled bone marrow after transplantation into rat cerebral infarct

AIM:To investigate the role of SDF-1α in migrating of bone marrow stromal cells to the injured areas.METHODS:Ischemic brain lesion model was created in rats by permanent middle cerebral artery occlusion (MCAO).48 SD rats were divided randomly into 2 groups.Group 1:phosphate buffered saline (PBS 1 mL) for control (n=25); Group 2:BMSCs (2×106) were injected intravenously at 24 h after MCAO (n=24).After propagated in BMSCs, Ad5/F35 GFP (green fluorescent protein) was infected to BMSCs.The expression of SDF-1α (stromal cell-derived factor-1α) mRNA in the penrumbral tissue was assayed by real-time quantitative PCR.The expression of CXCR4 on MSCs was detected by flow cytometry.Confocal microscopy was used to detect the GFP-labeled MSCs migration.RESULTS:Ad5/F35 GFP signals was observed in almost infected BMSCs.The expressions of SDF-1α mRNA in the thalamus and hippocampus of the ischemic brains were peaked at 3rd day after stroke, followed by a decrease at 14th day post-ischemia.The expression of SDF-1α mRNA in the cortex of the ischemic brains was peaked at 7th day post-ischemia, still at high level at 14th day post-ischemia.The median percentage of surface CXCR4 expression in BMSCs was 14%.GFP labeled BMSCs were detected in the origination of the middle cerebral artery (olfactory area) at 6 h, after 3 days in the prenumbra tissue such as thalamus, and in the cortex more labeled cells were found after 14 d post-ischemia.CONCLUSION:BMSCs can pass through the blood brain barrier of ischemic rats.Its mechanism might be associated with the expression of SDF-1α in the ischemic brain.