具有感觉传入通路的膀胱反射弧治疗脊髓损伤后弛缓性膀胱的实验研究

An experimental study on effect of bladder reflex arc with sensory afferent pathway in the treatment of atonic bladder after spinal cord injury

目的用SD大鼠构建具有感觉传人通路的膀胱反射弧，探讨其用于治疗脊髓损伤后弛缓性膀胱的有效性。方法SD雄性大鼠24只，右侧为实验侧，先行L5前根近断端与S2前根远断端吻合，再将L5脊神经节周围突支近断端与S2后根远断端行端端吻合。左侧不做处理，为对照侧。术后3个月，破坏L6-S4节段脊髓造成弛缓性膀胱，于建模前后通过一般观察、神经电生理检测、神经示踪等方法观察反射弧构建情况。结果21只大鼠存活至术后3个月，7只成功分离出吻合的脊神经。电刺激实验侧S2后根吻合口远端，均能检测到膀胱神经丛复合动作电位、膀胱平滑肌复合肌肉动作电位，截瘫前后动作电位差异无统计学意义；电刺激对照侧S2后根，在截瘫后未能检测到动作电位。实验侧膀胱神经丛复合动作电位和膀胱平滑肌复合肌肉动作电位平均波幅为截瘫前对照侧的71．9％和82．4％。神经示踪结果显示实验侧L5脊髓前、后角均可见青蓝色阳性反应颗粒。结论构建具有感觉传入通路的膀胱反射弧，可使其运动、感觉神经通过轴突再生长入副交感神经纤维，并与脊髓前、后角重建轴突联系，轴浆运输功能得到重建，可用于弛缓性膀胱的治疗。

Objective To establish bladder reflex arc with sensory afferent pathway using SD rats, and evaluate its effect in the treatment of atonie bladder after spinal cord injury. Methods Twenty-four male SD rats were used in the study. For each rat, the right side was the experimental side, and the left side was the control side. In the right side, the L5 ventral root （VR） was anastomosed to S2 VR, and the distal end of S2 dorsal root （DR） was anastomosed to the proximal end of L5 peripheral process of dorsal ganglion. In the left side, no treatment was done. In order to evaluate the validity of the bladder reflex arc, general observa-tion, neuro-electrophysiologieal test and wheat germ agglutinin horseradish peroxidase （WGA-HRP） method were used before and after the spinal cord destruction between L6 and S2 level at 3 months postoperatively. Results Twenty-one rats survived 3 months after the operation, and anastomotic nerves were separated suc-cessfully only in seven rats. Compound action potentials （CAPs） of plexus vesiea and compound muscle ac-tion potentials （CMAPs） of bladder smooth muscle were found by electrical stimulation in distal end of the anastomotic stoma of the right S2 DR. There was no statistically significant difference in action potential be-fore and after paraplegia. No action potential was detected in eontrol sides after paraplegia. The curves of CAPs and CMAPs in the right side were similar to those in the control side, and the mean maximum ampli-tude reached respectively 71.9% and 82.4% of those in the left side before paraplegia. In addition, WGA-HRP labeled cells were observed in L5 anterior horn and posterior horn in the experimental side after WGA-HRP injection. Conclusion Reconstruction of bladder reflex arc with sensory afferent pathway can promote axonal regeneration of motor and sensory nerves, and then the regenerated axon could contact with cells in anterior and posterior horn of spinal cord through parasympathetic nerves, ultimately the capability of axo-plasmic transportation could be reestablished. Therefore, this method can be used for treating atonie bladder.