Ohnishi N, Horan P, Levin S S, Levin R M
Division of Basic and Pharmaceutical Sciences, Albany College of Pharmacy, New York 12208, USA.
J Urol. 2000 Jan;163(1):292-5.
The initial response of the urinary bladder to outflow partial obstruction consists of distension, followed by a rapid increase in mass and concomitant functional adaptations. Subsequently, an indeterminate period of stabilized function and little increase in mass occurs (compensation). Finally, bladder mass again progressively increases, accompanied by deleterious changes in bladder morphology, biochemistry and pharmacology, and progressive loss of function (decompensation). The reported study was designed to determine whether limiting the level of bladder distension, using intermittent catheterization (IntCath), could protect the bladder from decompensation.
Sixteen male New Zealand White rabbits were separated into 4 groups of 4 rabbits each: control, control with IntCath, obstructed, and obstructed with IntCath. IntCath was performed with the animals under inhalation anesthesia. An 8 Fr. catheter was inserted through the urethra into the bladder every 8 hours and the urine drained. After 14 days of obstruction, bladders were removed from all rabbits; longitudinal strips were cut from the bladder body and suspended in individual organ baths. Contractile responses to field stimulation (FS), KCl, ATP, and carbachol were measured.
There were no significant differences between control rabbits and controls with IntCath in bladder weights, compliance, and contractile responses to all stimuli. Bladder weights of both obstructed groups increased significantly compared to those of both control groups. Bladder weights of obstructed rabbits increased to a significantly greater extent than did those of obstructed rabbits with IntCath. Bladder compliance in the obstructed group was significantly lower than compliance in both control groups and in obstructed rabbits with IntCath. Both obstructed groups exhibited significantly decreased contractile responses to FS, ATP and KCl, compared to control groups. The response of the obstructed group with IntCath to FS and carbachol was significantly greater than the responses of the obstructed group without IntCath.
These findings show that limiting distension with IntCath reduces the magnitudes of the increased bladder mass, the loss of bladder wall elasticity (compliance), and the impaired contractile responses which occur secondary to outflow obstruction.
膀胱对流出道部分梗阻的初始反应包括扩张，随后质量迅速增加并伴有功能适应性变化。随后，会出现一段功能稳定且质量增加很少的不确定时期（代偿期）。最后，膀胱质量再次逐渐增加，同时伴有膀胱形态、生物化学和药理学的有害变化以及功能的逐渐丧失（失代偿期）。本报告的研究旨在确定使用间歇性导尿（IntCath）限制膀胱扩张程度是否能保护膀胱免于失代偿。
16只雄性新西兰白兔被分为4组，每组4只：对照组、IntCath对照组、梗阻组和IntCath梗阻组。IntCath操作在吸入麻醉下对动物进行。每8小时通过尿道将一根8F导管插入膀胱并引流尿液。梗阻14天后，从所有兔子身上取出膀胱；从膀胱体切取纵向条带并悬挂在单独的器官浴槽中。测量对场刺激（FS）、氯化钾（KCl）、三磷酸腺苷（ATP）和卡巴胆碱的收缩反应。
对照组兔子与IntCath对照组在膀胱重量、顺应性以及对所有刺激的收缩反应方面无显著差异。与两个对照组相比，两个梗阻组的膀胱重量均显著增加。梗阻组兔子的膀胱重量增加幅度明显大于IntCath梗阻组兔子。梗阻组的膀胱顺应性显著低于两个对照组以及IntCath梗阻组兔子。与对照组相比，两个梗阻组对FS、ATP和KCl的收缩反应均显著降低。IntCath梗阻组对FS和卡巴胆碱的反应显著大于无IntCath梗阻组。
这些发现表明，通过IntCath限制扩张可减少膀胱质量增加的幅度、膀胱壁弹性（顺应性）的丧失以及流出道梗阻继发的收缩反应受损。
