Saito M, Yokoi K, Ohmura M, Kondo A
Department of Urology, Nagoya University School of Medicine, Japan.
Urol Int. 1997;59(4):226-30. doi: 10.1159/000283068.
Detrusor dysfunction secondary to partial outflow obstruction is caused in part by decreased blood flow to the detrusor. We investigated changes in blood flow to the bladder and in bladder function after inducing partial outflow obstruction. The urethras of male Sprague-Dawley rats were constricted by sutures to degrees representing either mild and severe obstruction. Blood flow to the bladder was measured by a Doppler flowmeter prior to and 7 days after obstruction. In vivo and in vitro experiments were performed 7 days after surgery. After cystometry was used to determine bladder capacity, the pressure at which micturition was induced, and maximum voiding pressure, the bladder was removed and placed in an organ bath where increases in intravesical pressure in response to field stimulation were evaluated. Finally, volume-pressure studies were performed in order to determine passive detrusor compliance and response to field stimulation at each specific capacity in vitro. Although blood flow to the bladder was significantly decreased by severe obstruction, no differences in blood flow between control and mildly obstructed bladders was observed. While maximum voiding pressure decreased in severely obstructed bladders, both the pressure at which micturition was induced and bladder capacity were increased. The response to field stimulation was increased by mild obstruction but decreased by severe obstruction, although bladder compliance was increased by both. The peak response to filled stimulation was observed at a larger capacity in severely obstructed bladders than the others. In conclusion, when outflow obstruction was mild, blood flow to the bladder remained unchanged and detrusor contractility increased. On the other hand, severe obstruction decreased bladder blood flow and induced deterioration of detrusor function.
部分流出道梗阻继发的逼尿肌功能障碍部分是由逼尿肌血流减少引起的。我们研究了诱导部分流出道梗阻后膀胱血流及膀胱功能的变化。通过缝合将雄性Sprague-Dawley大鼠的尿道狭窄至轻度和重度梗阻程度。在梗阻前及梗阻7天后，用多普勒流量计测量膀胱血流。术后7天进行体内和体外实验。在通过膀胱测压法测定膀胱容量、诱发排尿的压力及最大排尿压力后，将膀胱取出并置于器官浴槽中，评估其对场刺激的膀胱内压升高情况。最后，进行容量-压力研究以确定体外每个特定容量下的被动逼尿肌顺应性及对场刺激的反应。虽然重度梗阻使膀胱血流显著减少，但未观察到对照组与轻度梗阻膀胱之间的血流差异。重度梗阻膀胱的最大排尿压力降低，而诱发排尿的压力和膀胱容量均增加。轻度梗阻使对场刺激的反应增强，而重度梗阻则使其减弱，不过两者均使膀胱顺应性增加。重度梗阻膀胱对充盈刺激的峰值反应出现在比其他膀胱更大的容量时。总之，当流出道梗阻为轻度时，膀胱血流保持不变，逼尿肌收缩力增加。另一方面，重度梗阻会减少膀胱血流并导致逼尿肌功能恶化。
