Intracranial bone marrow transplantation after traumatic brain injury improving functional outcome in adult rats

Object. The authors tested the hypothesis that intracranial bone marrow (BM ) transplantation after traumatic brain injury (TBI) in rats provides thera peutic benefit. Methods. Sixty-six adult Wistar rats, weighing 275 to 350 g each, were used for the experiment. Bone marrow prelabeled with bromodeoxyuridine (BrdU) w as harvested from tibias and femurs of healthy adult rats. Other animals we re subjected to controlled cortical impact, and BM was injected adjacent to the contusion 24 hours after the impact. The animals were killed at 4, 7, 14, or 28 days after transplantation. Motor function was evaluated both bef ore and after the injury by using the rotarod test. After the animals had b een killed, brain sections were examined using hemotoxylin and eosin and im munohistochemical staining methods. Histological examination revealed that, after transplantation, BM cells survived, proliferated, and migrated towar d the injury site. Some of the BrdU-labeled BM cells were reactive, with as trocytic (glial fibrillary acid protein) and neuronal (NeuN and microtubule -associated protein) markers. Transplanted BM expressed proteins phenotypic al of intrinsic brain cells, that is, neurons and astrocytes. A statistical ly significant improvement in motor function in rats that underwent BM tran splantation, compared with control rats, was detected at 14 and 28 days pos ttransplantation. Conclusions. On the basis of their findings, the authors assert that BM tra nsplantation improves neurological outcome and that BM cells survive and ex press nerve cell proteins after TBI.