糖尿病对大鼠尿道外括约肌功能的损害

目的利用大鼠模型研究糖尿病（DM）对尿道外括约肌功能的影响。方法以雌性SD大鼠制成DM模型,6-8周后测定DM大鼠和正常对照（NC）大鼠膀胱等容收缩状态下的膀胱内压、尿道充盈压和括约肌肌电图（EUS-EMG）。结果与NC大鼠对比,DM大鼠体重明显降低,血糖明显升高,膀胱容量明显增大;膀胱排尿收缩时尿道压力病理性增高;EUS-EMG表现为排尿过程中应有的尿道外括约肌高频舒张收缩减弱或消失,引发的尿道压力曲线上的高频振动波振幅降低或消失。结论DM在损伤大鼠膀胱功能的同时,还损伤排尿时尿道外括约肌正常的高频收缩舒张功能。

External urethra sphincter dysfunction in diabetic female rats

Objective Urethral function is essential for efficient voiding. This study focused on the function of the external urethral sphincter （EUS） in DM rats. Methods Female SD rats voith the weight of 250-275g weight initially were Used. DM （n=6） was induced by an i. p. injection of streptozotocin （65 mg/kg） and allowed to progress for 6 to 8 weeks, and age-matched normal rats （n= 5） were taken as control. A double lumen catheter was used to simultaneously record isovolumetric bladder pressure and urethral perfusion pressure （UPP） under urethane anesthesia. EUS-EMG（electromyogram） activities were also recorded using fine wired electrodes. Results Blood glucose of all DM rats was〉300 mg/dl. High frequency oscillations （HFOs） of UPP were significantly reduced in some diabetic rats, but never in controls. The increased tonic EUS activity in diabetic rats resulted in increased urethral resistance （UPP was 23.5±1.6mmHg in DM rats compared with 7.9±1.8mmHg in controls,P〈0.05）. Conclusions These results demonstrate that DM induces EUS dysfunctions, decreases urethral relaxation and increases urethral outlet resistance during reflex voiding.