[Treatment of spinal cord injury by transplanting neural stem cells with NgR gene silencing].

OBJECTIVE

To determine whether Nogo-66 receptor (NgR) gene silencing in neural stem cells (NSCs) can ameliorate spinal cord injury (SCI) in rats.

METHODS

The brain tissue of Wistar rats of embryo (age 14-16 days) was obtained, and NSCs were cultured in suspension culture, and they were transfected by siRNA to silence the expression of NgR. Western blotting was used to assess the silencing efficiency. Thirty-six Wistar rats were divided randomly into three groups. Hemi-truncation of right-half side of 8, 9 thoracic spinal cord was performed. Group A was injected same amount of culture medium without NSCs, B group was given naive NSCs suspension, and C group same amount of NgR gene silenced NSCs. At 1, 2, 4, 6, 8 weeks post-injury, the motor power of the hind limbs of all animals were evaluated with inclined plane test. The tissue of the injured portion of spinal cord was obtained for pathological examination with hematoxylin and eosin (HE) and 5-bromodeoxyuridine(BrdU) immunohistochemistry staining after 4 weeks, and observed with horseradish peroxidase (HRP) nerve trace techniques after 8 weeks.

RESULTS

Western blotting confirmed that the expression of NgR was down-regulated by transfection of siRNA at 24 hours after the transfection (1.03+/-0.08 vs. 1.88+/-0.15, P=0.002). Inclined plane test showed the performance was improved in B and C groups, and that of C group surpassed that of B group after 8 weeks (P<0.05). In A group, there was no passage of axons through the injury, while in B and C groups, there were several nerve axon-like structure in the injured part. BrdU positive cells and HRP-labeled neurofibrils in C group>B group>A group (BrdU positive cells: A group 39.82+/-14.07, B group 91.68+/-12.34, C group 103.67+/-11.52, HRP-labeled neurofibrils: A group 11.35+/-1.71, B group 39.87+/-2.42, C group 83.64+/-2.13), and there was statistical significance among three groups (all P<0.01).

CONCLUSION

Transplantation of NSCs of NgR gene silencing transplants into the injured spinal cord tissue can significantly improve the neurological function in the rats.