Recovery law of hind limb function following complete spinal cord transection injury in rats / 中华创伤杂志

ABSTRACT

Objective To observe the recovery process of hind limb function following complete spinal cord transection injury and discuss corresponding mechanism. Methods The spinal cords of 15 SD rats were transected at T9 plane and a 3 mm spinal cord removed for a complete transection. The functional recovery of the hind limb was evaluated using CBS (combined behavioral score) and Basso Beattle Bresnahan (BBB) 1, 2, 4 and 6 weeks after injury. At the 6th week after injury, also experiment was done on histology, immunohistochemistry, motor evoked potential (MEP) of spinal cord and repeated transection. Results The hind limb function of the injured animals recovered at different degrees, most obvious at the 4th week and BBB was up to 12 at the 6th week. MEP result was related to the site of the stimulating electrode. No MEP was recorded when the stimulating electrode was placed above the injured site. But when the stimulating electrode was placed below the injury level, MEP was normal. The again transection of the spinal cord above the injury level took no effect on the recovered hind limb. However, again transection below the injury level resulted in complete paralysis. Histologic results showed that the injured site was filled with glial scars without axons. There existed a little scattered positive fibers of neurofilament protein 200 (NF200). Conclusions After complete spinal cord injury, there is a significant spontaneous recovery of the hind limb function that is a kind of autonomous functions of the injured distal spinal cord unrelated to repair of descending conducting fasciculus of the spinal cord. The distal spinal cord is intact in function.