膀胱出口梗阻所致逼尿肌过度活动的神经电生理研究

摘要

目的 从膀胱传入神经以及盆底相关神经肌肉角度探讨神经因素及肌源性因素在膀胱出口梗阻所致的逼尿肌过度活动发生中的作用.方法 采用耻骨上膀胱颈梗阻的方法建立逼尿肌过度活动大鼠模型,测定不稳定收缩时盆神经传入电位信号,并同步测定阴部神经运动支电位、尿道外括约肌肌电及腹肌肌电的反射反应.并观察T8段脊髓截断、双侧盆神经截断、腹交感干截断以及双侧阴部神经截断后大鼠膀胱充盈测压不稳定收缩的变化.结果 成功制作了膀胱出口梗阻逼尿肌过度活动大鼠模型,成功率62.5%.充盈性膀胱测压神经肌电生理同步记录结果显示,允盈期逼尿肌过度活动可分为两种类型,一种为收缩幅度高于10 cmH2O(1 cmH2O=0.098 kPa)的逼尿肌过度活动(B-DO),伴有同步盆神经传入的信号明显增强,且能引发阴部神经、尿道外括约和腹肌肌电图出现显著变化;一种为收缩幅度低于10 cmH2O的逼尿肌过度活动(S-DO),没有上述盆神经传入及相关神经肌电变化.T8脊髓截断后,膀胱充盈-排尿收缩周期消失,膀胱基础压显著升高,B-DO消失,S-DO仍然存在,且收缩幅度较截断前略有上升,但差异无统计学意义.依次截断控制膀胱的盆神经、交感神经和阴部神经后,膀胱失去充盈-排尿收缩周期,基础压显著升高,不稳定收缩中B-DO消失,S-DO仍然存在.结论 膀胱出口梗阻所致的逼尿肌过度活动存在不依赖于中枢和周围神经的膀胱源性因素.%Objective To study the neurophysiologic of detrusor overactivity (DO) due to partical bladder outflow obstruction (PBOO). Methods Twenty four female Wistar rats with DO caused by PBOO were studied simultaneously with ten sham-operated rats. An electrophysiological multi-channel simultaneous recording system was used to record pelvic afferent fiber potentials as well as the pudendal nerve motor branch potentials, external urethral sphincter electromyogram (EUS EMG) and abdominal muscle EMG during filling cystometry. To test the effect of the unstable contraction in DO rats after the decentralization of the central nervous system, DO rats were studied the changes of the unstable contraction after transection of the spinal cord (T8 level), pelvic nerve, the 8ympathetic trunk, and the pudendal nerve. Results The incidence of DO was 62. 5% in filling cystometry. During filling cystometry, there are two type of DO contraction according to the changes of pelvic afferent fiber signals, the relevant nerves and muscles responses:the small pressure of the unstable contraction (S-DO) and the big pressure of the unstable contraction (B-DO). For the B-DO, there were significant changes in the recordings of pelvic afferent fiber,the motor branch of the pudendal nerve, EUS EMG, and abdominal muscle EMG. While all these differences have not been recorded during S-DO. Both the fillling-voiding cycle and the unstable contraction of B-DO were eliminated and the base line of bladder pressure increased after T8 spinal cord transection. While the S-DO was not affected by such transection. When bladder relevant nerves were transected by the sequence of the pelvic nerve, the sympathetic trunk, and the pudendal nerve, the filling-voiding cycle was eliminated. The base line of bladder pressure increased significantly. No B-DO was recorded, but the S-DO still existed. Conclusion There are some bladder-genic factors take part in the DO contractions induced by PBOO.