Chronergical study on intravenous transplantation of umbilical blood mesenchymal stem cells after ischemic-hypoxic brain damage in neonatal rats

Objective To study the feasibility and chronergy of intravenous transplantation of the human umbilical blood mesenchymal stem cells (MSCs) after hypoxic-ischemic brain damage (HIBD) in neonatal rats.Methods Human umbilical MSCs were cultured and labeled with 4′,6-Diamidino-2-phenylindole dihydrochloride hydrate (DAPI).Among the 38 rats for HIBD model establishment,3 rats died and the rest HIBD rats were divided into 3 groups:Control group(n=11);MSCs transplant group one(n=12,the MSCs were grafted at the second day after HIBD) and MSCs transplant group two(n=12,the MSCs were grafted at the second week after HIBD).The human umbilical DAPI-labeled MSCs were grafted via the caudal vein of rats.After the rats in each group were randomly sacrificed at the second day after implantation or the second week after HIBD,brain tissue was examined pathologically and DAPI-positive cells in hippocampal gurus were counted under the fluoroscope.Results One week after transplantation,transplant group two showed less cell swelling,smaller extracellular space and more migratory cells.Moreover,DAPI-labeled MSCs were present in the damaged brain tissue of transplant group two,suggesting MSCs could cross the blood brain barrier (BBB) to migrate into the hypoxic-ischemic lesion for tissue repair.But these changes mentioned above weren't obvious in transplant group one.Conclusion The human umbilical blood MSCs transplantation for the HIBD treatment in the neonate rats at the second week after HIBD can effectively decrease the brain edema and relieve brain tissue damage;MSCs can cross the BBB and migrate into hypoxic-ischemic lesion.Furthermore,implantation response and adverse effects were absent in our study.