肛门失禁动物模型的构建及评价

Establishment and evaluation of rabbit model of fecal incontinence

目的构建成年新西兰兔肛门失禁动物模型。方法选取12只成年健康雄性新西兰兔,按随机数字表完全随机分为2组:实验组和对照组。功能性定位兔肛门外括约肌双侧支配神经,即第4骶神经,相当于人体解剖学中的骶神经,实验组局部注射50g/L罗哌卡因,选择性破坏该神经,对照组注射生理盐水。检测操作前后肛管内静息压力的变化,观察第4骶神经及其效应肌的神经肌电图和组织病理学变化。结果与对照组相比,实验组兔术后肛管内静息压力明显下降。神经肌电图显示术后实验组第4骶神经传导异常。透射电镜显示实验组第4骶神经轴索不可逆性改变。结论局部注射药物破坏肛门外括约肌双侧支配神经可成功制作出紧迫失禁的动物模型,为进一步做人工肛门体内实验研究提供了参考。

Objective To establish and evaluate a rabbit model of fecal incontinence. Methods Twelve normal adult male New Zealand rabbits were randomly divided into experimental group and control group. The nerve innervating the external anal sphincter, namely the fourth sacral nerve, was functionally located and selectively damaged with local injection of 50 g/L ropivacaine in the experimental group, and normal saline injection was administered in the control group. The changes in the resting anal pressure was examined before and after the surgery, and the electromyogram （EMG） of the external anal sphincter was recorded for comparison with the pathological changes of the fourth sacral nerve. Results Compared with the control group, the experimental group exhibited significantly decreased resting anal pressure after the surgery. The EMG of the experimental group showed abnormal nerve conduction velocity of the fourth sacral nerve, suggesting successful nerve block. Transmission electron microscope revealed irreversible pathological changes in the ultrastructure of the axons of the fourth sacral nerve. Conclusions This method allows successful establishment of fecal incontinence in rabbits, which facilitates further in vivo study of artificial sphincters for treatment of anal incontinence.