OBJECTIVETo investigate the effects of olfactory ensheathing cells (OECs) transplantation and treadmill training in improving hindlimb motor function of spinal cord injury(SCI) rats and explore its possible mechanism.

METHODSA total of 80 male SD rats were randomly divided into four groups: media untrained (group A), OECs untrained (group B), media trained (group C) and OECs trained(group D). Each group had 20 rats and all rats were made the model of spinal cord injury. The rats of group C and D underwent treadmill exercise in 3 days after operation, the rats of group B and D underwent OECs transplantation in 7 days after operation (each rat was injected a total of 4 μl, cell concentration was 1.0×10₆/μl), at the same time, the rats of group A received the corresponding dose of saline. Then observed was continued for 4 weeks totally. BBB scores in each group were measured weekly. The expression of Bax, Bcl-2, NF-200 were observed by immunohistochemisty staining. Mallory staining was used to the regeneration of nerve fibers and TUNEL staining was used to observe neuronal apoptosis.

RESULTS(1)The BBB scores in group D in the 4th week was significantly higher than of other three groups(<0.05). (2)On the Bcl-2 protein expression, there was interaction between OECs and treadmill training, the two mutually reinforcing;while OECs transplantation can significantly reduce the Bax protein expression without significant interaction with treadmill training(>0.05). TUNEL staining showed that OECs transplantation, treadmill training, the time factor had an interaction and significantly inhibited the apoptosis(<0.05). (3)It was showed in immunohistochemisty staining of NF-200 and Mallory staining that OECs transplantation, treadmill training with the time factor were an interaction among the three with significant regeneration of nerve fibers(<0.05).

CONCLUSIONSOECs transplantation combined with treadmill training can significantly improve hindlimb motor function of SCI rats, which may be achieved by the following ways. OECs transplantation and treadmill training can collaborate with each other, significantly increasing the expression of Bcl-2 gene, which significantly inhibit neuronal apoptosis;at the same time it can promote neuronal axonal regeneration, increase the number of nerve fibers, and this effect may be more remarkable with time.