Abstract: Objective To investigate the functional recovery and effects of the bone marrow mesenchymal stem cells (BMSCs) transplanted by abdominal aortic on apoptosis and caspase9 in spinal cord ischemic reperfusion injured (SCIRI) rats. Methods 24 adult female SD rats were assigned randomly to 3 groups (8 rats in each group). Rats in the sham group were subjected to the operative procedure but short of blocking abdominal aorta. Rats in the control group and the transplantation group were subjected to abdomen aorta occlusion for 120 min to induce spinal cord ischemia, and then the aorta was reopened for spinal cord reperfusion. Five minutes later, 10% FBS culture medium and BMSCs suspension were injected by the arterial trocar respectively. BBB scores was assessed at 1, 3 and 7days after the operation. RT-PCR and Western blot were used to detect the expressional changes of caspase9 and TUNEL was used to observe apoptosis in the lumbar segments of spinal cord. Result Compared with the sham group, BBB scores in the transplantation group and the control group decreased obviously at 1, 3 and 7days post operation (P<0.01). However, the scores in the transplanted rats were much higher than that in the control group (P<0.01). The mRNA and protein level of caspase9 was increased greatly in the SCIRI rats, but the level in the transplantation group was lower than that in the control group (P<0.01). Apoptosis had been detected in the injuried cords, the number of apoptosis in the transplantation group was fewer than that in the control group (P<0.01). Conclusion BMSCs, transplanted by the abdominal aorta, can promote the functional recovery by inhibiting the expression of caspase9 and reducing the occurrence of apoptosis in the injuried spinal cord.

Key words: Spinal cord, Ischemic-reperfusion injury, Abdominal aorta, Bone marrow mesenchymal stem cells (BMSCs), Transplantation, Apoptosis