Experimental study of reconstruction of hindlimp movement with spinal ventral root anastomoses after spinal cord injury in rats

Abstract

Objective To establish a paraspinal neural pathway of quadriceps femoris by end-to-end anastomoses between the spinal ventral root after spinal cord injury(SCI) in rats. Methods Twenty-fourweek old SD rats, with the weight of 120 g to 150 g, were included. The left side was the experimental side, while the right side served as a control. Electrostimulating of L1-L5 ventral root was done respectively to decide the predominant nerve of quadriceps femoris. The lumbar 1 ventral root was reveal to little innervation of quadriceps femoris, and the lumbar 3 ventral root was predominant innervation. End-to-end anastomosis between the left L1 and L3 ventral root was done. After axona regeneration, the new paraspinal neural pathway of quadriceps femoris was established. At 6 months postoperatively, the early function of the new pathway was observed by electrophysiological examinations, hindlimb locomotion and BBB (basso, beattie and bresnahan)scale at 1,3,7, 14,21,28 d after SCI. Results Sixteen rats survived for 6 months after operation and only ten rats got good results because of tissue adhesion postoperatively. Single stimuli (2.5 mA,0.2 ms, 1 Hz) of the left anastomoses nerve resulted in action potential recorded from the left quadriceps femoris before and after the spinal cord hemisection horizontally between L2 segmental levels. The amplitudes of the action potentials were (7.63 ± 1.86) mV and (6.00 ± 1.92)mV, respectively, and there was no significant difference (P ＞ 0.05). The left quadriceps femoris contraction was initiated by single stimuli (2.5mA, 0.2 ms, 1 Hz) of the left anastomoses nerve. After paraplegia, when the right L3 ventral root was stimulated, the amplitude of the action potential was (15.87 ± 1.16) mV. Locomotion of the left hindlimb was partially restored after spinal cord hemisection while creeping and climbing. According to BBB scale, there was significant difference at 1, 3, 7 d, and little difference at 14, 21, 28 d after SCI. Conclusion Spinal ventral roots cross-ananstomosis to reconstruct the paraspinal pathway of quadriceps femoris after SCI is efficient reinnervation of hindlamb muscles in a rat model and may have potential in clinical application. Key words: Spinal cord hemisection;  Quadriceps femoris;  Spinal nerves;  Nerve anastomosis