Therapeutic time window and effect of intracarotid neural stem cells transplantation for intracerebral hemorrhage

This study investigated the therapeutic effect of neural stem cells transplanted via the carotid artery at different times after intracerebral hemorrhage. A great number of 5-bromo-2-deoxyuridine-positive cells were observed surviving and distributed evenly in the perihematoma areas. Phenotypes of grafted cells depended upon time of transplantation, and the later the cells were transplanted, the larger the percentage of cells that differentiated into neurons. Animals treated at 7 and 14 days after injury exhibited the most significant improvements in behavioral tests. Therefore,intracarotid injection allows efficient delivery of cells to the injured hemisphere, especially during the period 7-14 days after injury, and may potentially be applicable in humans.