体神经-内脏神经反射弧建立后脊髓损伤鼠排尿功能的改变以及可能机制

目的 建立新的体神经-内脏神经反射弧,应用尿流动力学方法来检测新反射弧建立后对清醒脊髓损伤(SCI)鼠膀胱功能及逼尿肌-尿道外括约肌协调性的影响以及可能机理。方法成年雄性大鼠(280～300)g在L4～L6的椎管内行L6腹侧根与L4腹侧根神经端端吻合,保留L4背根来传导来自新反射弧的皮肤传入信号。术后3个月行T9～T10椎间脊髓横断,8周后在清醒状态下检测容量诱发性排尿和电刺激新反射弧皮肤感觉传入区诱发排尿的膀胱压力变化图(CMG)和尿道外括约肌肌电图(EUS-EMG)各项参数的变化。结果 新的体神经-内脏神经反射弧建立后,在清醒状态下电刺激L4皮区可以诱发排尿,和不用电刺激的容量诱发性排尿(VEMR)相比排尿量增加、排尿压提高、排尿开放压提高,而残余尿减少,排尿效率明显增加,差异均有显著性(P<0.05)。EUS的肌电频率明显降低。结论 新反射弧建立后使 SCI鼠的排尿功能发生显著改变。电刺激反射弧的皮肤感觉区可以收缩膀胱逼尿肌使膀胱内压升高并同时使尿道外括约肌肌电频率下降,CMG和EUS的多项参数均有改善。逼尿肌-外括约肌不协调得到改善。

Effect of artifical somatic-autonomic reflex arc on micturition after spinal cord injury and its underlying mechanisms

Objective A new artifical somatic-autonomic reflex arc has been estabilished in male SCI rat for inducing micturition. Urodynamic and electrophysiological studies were conducted in such ani- mal model after estabilishing the new reflex arc to analyze the mechanisms and the effects to voiding. Methods In normal male Sprague-Dawley rats weighing 280-300 g, under anesthesia the rats were sub- jected to limited laminectomy of L4--L6 vertebrae to expose the spinal cord, and the new reflex arc was es- tabished by intradural microanastomosis of left L4 vetral root to the L6 vetral root while leaving the L4 doral root intact to conduct cutaneous afferent signals that could trigger the new micturition reflex arc. Three months later the spinal cord was completely transected at the T9-10 level. Eight weeks later CMG and EUS-EMG were conducted about voiding elicited by volume-evoked micturition reflex (VEMR) or by electrical stimulating in L4 dermatome. Results In conscious station percutaneous electrical stimula- tion could initiate voiding. Compared with VEMR voiding initiated by electrical stimulation had lager voiding volumes, higher micturition pressure and higher press threshold. The residual volumes were de- creased and voiding efficiency was improved. The EUS bursting activity frequency was decreasd. Conclu- sion The new artifical somatic-autonomic reflex arc is effective in initiationg bladder contractions and coordinated voiding in SCI rats.