构建犬“腹壁反射-脊髓中枢-膀胱”人工反射弧功能基础的实验研究

Construction of a reflex arc of abdominal reflex-spinal cord-bladder in canines

目的:探讨构建犬"腹壁反射-脊髓中枢-膀胱"人工反射弧,以恢复脊髓损伤后的膀胱功能。方法:对6只雄性犬麻醉后进行T12和S2神经的解剖,将T12前根近端与S2前根远端通过一段尾神经在硬膜囊内行显微缝合,保持T12后根完整,经过一段时间轴突再生后,建立"腹壁反射-脊髓中枢-膀胱"人工膀胱反射弧。神经根吻合术后6个月和18个月,分别在破坏L5～S2脊髓节段前后进行膀胱神经电生理、膀胱测压、膀胱逼尿肌肌电图等早期和远期功能观察。结果:实验侧膀胱神经动作电位和膀胱逼尿肌肌电图,其形态与波幅与对照侧相似。1、2、4号犬术后6个月截瘫48h后,电刺激经新建的反射弧引出的膀胱收缩平均可达正常对照组71.80%,5、6号犬术后18个月,相同电流刺激引出的膀胱收缩平均达正常的84.42%。结论:体神经的运动传出支经自体神经移植,其轴突能再生长入膀胱平滑肌内副交感神经节细胞,并具有良好的传导运动兴奋的功能;构建犬"腹壁反射-脊髓中枢-膀胱"人工反射弧,可望实现脊髓损伤患者膀胱可控性排尿功能。

Objective To construct a reflex are of abdominal reflex-spinal cord-bladder for restoring bladder function in canines with spinal cord injury. Methods The nerves T12 and S2 were separated and revealed in 6 male canines after anesthesia. An intramural microanastomosis of the proximal end of the left T12 ventral root to the distal end of the left S2 ventral root was performed by a coccygeal nerve graft, with an intact left T12 dorsal root. With axonal regeneration, a reflex arc of abdominal reflex-spinal cord-bladder was developed. At months 6 and 18 after the procedure, electrophysiological assessment of the bladder, cystometry, and electromyography of the detrusor muscle were performed before and after the horizontal damage to L5-S2. Results The experimental side of the bladder was similar to the control side in the shape and amplitude of the nerve action potential and the electromyogram. At month 6, the frequency of bladder contraction induced by the electrical stimulation via the established arc in the experimental side reached up to 71.80% of that in the control side in canines 1, 2, and 4. At month 18, the frequency was up to 84.42% of that in the control side in canines 5 and 6. Conclusions The somatic motor axon can regenerat through a segment of autogenous nerve into a parasympathetic ganglion in the bladder smooth muscle. The construction of a reflex arc of abdominal reflex-spinal cord-bladder in canines provides basic evidence for clinical application to self-controlled urination in patients with spinal cord injury.