Effect of doxazosin on rabbit bladder compliance after partial bladder outlet obstruction / 中华泌尿外科杂志

Objective To explore the effect of doxazosin on rabbit bladder compliance after partial bladder outlet obstruction. Methods A total of 40 male New Zealand white rabbits were randomized into 4 groups, with 10 rabbits in each group. Partial bladder outlet obstruction was established in groups B and C, while groups A and D underwent the same operation but without partial bladder outlet obstruction. On the day after the operation, groups C and D received oral administration of doxazosin. After 14 weeks, urodynamic examinations were carried out in all groups, and the bladder was weighted after cystectomy. Results Bladder weight was (3.2±0.9) g in group A, (14.1±2.3) g in group B, (5.0±2.0) in group C,and (2.9±0.5) g in group D. The bladder weight in groups B and C increased significantly compared to groups A and D (P＜0.01), group B increased significantly over group C (P＜0.01), and there was no significant difference between groups A and D (P＞0.05).The detrusor leak point pressure was (10.2±2.5) cm H2O in group A, (18.8±6.1) cm H2O in group B, (13.5±4.7) cm H2O in group C,and (11.6±3.6) cm H2O in group D. The detrusor leak point pressure in group B was significantly higher than group A, group D (P＜0.01) and group C (P＜0.05). There was no significant difference between group A, group C and group D (P＞0.05). The bladder compliance was (2.86±0.56) ml/cm H2O in group A, (1.22±0.39) ml/cm H2O in group B, (4.25±2.19) ml/cm H2O in group C,and (2.90±0.53) ml/cm H2O in group D. The bladder compliance was significantly decreased in group B compared to groups A and D (P＜0.01). Bladder compliance in group C was significantly higher than in groups A and D (P＜0.05), and there was no significant difference between group A and group D (P＞0.05). Conclusion Early use of doxazosin can delay the occurrence of lower bladder compliance after partial bladder outlet obstruction, thus protecting the storage function of bladder.

Expression of Nitric Oxide Synthase(NOS) in Rat Bladders Subjected to Short-term Partial Outlet Obstruction / 대한비뇨기과학회지

PURPOSE: Nitric oxide synthase(NOS) is an important enzyme in the production of nitric oxide(NO). The constitutive type(cNOS) is expressed in the normal physiologic state, and the inducible type(iNOS) in expressed in the active immune state. cNOS is divided into an endothelial type (eNOS) and a neuronal type(nNOS). eNOS affects blood vessels, while nNOS affects nerve fibers. In the present study, we evaluated the expression of eNOS and nNOS in rat bladders with short-term partial outlet obstructions. We presupposed that NO is responsible for prolonged micturition problems after partial outlet obstruction. MATERIALS AND METHODS: Specific pathogen-free Sprague-Dawley rats weighing 250-300g were used for the study. Individual bladders were obtained from sham-operated control rats(n=5) and from experimental rats at 12 hours and 1, 2, 3, and 7 days after partial urethral obstruction(n=25). eNOS and nNOS were detected using immunochemical staining and analyzed with confocal microscopy and an image analyzer. RESULTS: eNOS and nNOS expression were detected in both the control group and in the group with partial outlet obstruction. The expression of eNOS showed a sharp increase at 3 days after obstruction and returned to normal at 7 days. The expression of nNOS was not significantly different between the two groups. CONCLUSIONS: In this study, we showed that eNOS increases in the rat bladder after partial outlet obstruction. This finding suggests that overproduction of NO may be the result of ischemic injury sustained during partial bladder outlet obstruction.

Changes in Corpus Cavernosum after Partial Bladder Outlet Obstruction in Rat / 대한비뇨기과학회지

PURPOSE: Abnormalities of the relaxation and contraction of the corpus cavernosum can lead to erectile dysfunction. Therefore, we induced a partial bladder outlet obstruction(PBOO) in male rats, and investigated the mechanisms of penile dysfunction with endothelial nitric oxide synthase(eNOS), vascular endothelial growth factor(VEGF), endothelin-1(ET-1), and apoptosis of peri-vascular smooth muscle and connective tissue cells in the corpus cavernosum. MATERIALS AND METHODS: PBOO was induced in 13 Sprague-Dawley rats by placing a 25 gauge needle sheath around the urethra, then ligating the bladder neck with a 3-0 suture. Three week after surgery, distal penile tissues were dissected for immunohistochemical staining, immunoblotting, and TUNEL staining. RESULTS: The expression of eNOS and VEGF were significantly decreased, whereas the expression of ET-1 and apoptosis of perivascular smooth muscle and connective tissue cells were significantly increased in the corpus cavernosum. CONCLUSIONS: The significant increase of ET-1 and apoptosis along with decreased eNOS and VEGF could mediate erectile dysfunction.

The Effect of Terazosin on the Histological Changes of Rat Bladder after Partial Outlet Obstruction

PURPOSE: When the bladder outlet is partially obstructed, The expression of iNOS and collagen type III is caused by ischemia of bladder. This study aimed to evaluate the hemodynamic changes and the expression of inducible nitric oxide synthase(iNOS) and collagen type III of bladder during acute stages of partial bladder outlet obstruction in female rats and conducted a research on the effect of alpha-adrenergic blocker. MATERIALS AND METHODS: Thirty mature Sprague-Dawley rats were randomly divided into three groups; 3 days(Group I), 7 days(Group II), 14 days(Group III), depending on the term of partial bladder outlet obstruction. After obstruction, each group was subdivided into the experimental groups and the control groups; terazosin(0.4 mg/kg) was administered to the experimental groups and normal saline was administered to the control groups for a week. The degree of expression of iNOS and collagen type III in bladder was investigated by immunohistochemical stain and Western blot. RESULTS: The blood flow of experimental groups showed significant increase compared to control groups(p<0.05). The expression of iNOS and collagen type III of exerimental groups was significantly decreased compared to the controls(p<0.05). CONCLUSION: This study suggests that alpha-adrenergic blocker makes increase in blood flows to bladder and may have a role of prevention from functional damage of bladder.

Evaluation on urodynamics of the partial bladder outlet obstruction model / 医学研究生学报

Objective: To establish a rabbit unstable bladder and Partial Bladder Outlet Obstruction (BOO) model, and to study on urodynamic changes. Methods: 30 male New Zealand rabbits were divided into control group and operative group. After 8 weeks, urodynamic changes were determined after they were anaesthetized by ketamine and droperidol. Results: Prominent changes of Main urodynamic parameters were found between the operative group and control group. The incidence rate of unstable bladder was 60%. Conclusion: The method of establishing rabbit model of Partial BOO is successful. It provides a platform for the study on the changes of pathology and pathophysiology of human chronic partial BOO and treatment of this kind of diseases.

In Vitro Responses of Alpha-adrenergic Antagonist of Rat Detrusor Muscle after Partial Bladder Outlet Obstruction / 대한비뇨기과학회지

PURPOSE: Our experiments were done to determine the effects of alpha-1-adrenergic antagonists which have been commonly used in the treatment of BPH against the partially obstructed detrusor smooth muscle using in-vitro muscle strip study of female rat bladder. MATERIALS AND METHODS: Partial obstruction was created by means of partial ligation of the proximal urethra in 15 female Sprague-Dawley rats. After 6 weeks of obstruction, 1x0.5cm sized each bladder smooth muscle strip was stimulated by field stimulation(FS),(1-32Hz) and bethanechol administration(10(-7)-10(-4)M). After the control stimulations, each strip was pre-treated with doxazosin, tamsulosin, prazosin and atropine for 30 minutes, and then same stimulations were repeated. Seperate strip was pre-treated by propranolol for 30 minutes, and then was stimulated by norepinephrine(10(-4)M) or phenylephrine(10(-4)M). RESULTS: After the administration of doxazosin, percent decreases of maximal tension developed by FS was significantly greater in obstructed(26-50% of the control) than in normal rats(0-12% of the control)(p<0.05). Field stimulated tension were inhibited more in normal(32-40%) than in obstructed rats(p<0.05, 1-32Hz) after the administration of prazosin. Atropine inhibited field stimulated tension to a greater degree in normal(73-63%) than in obstructed(27-43%) rats(p<0.01, 1-32Hz). Complete inhibitory effects of atropine against bethanechol stimulation(10(-7)-10(-4)M) was achieved at 10(-5)M in normal rats. In obstructed rats, complete blockage was achieved at 10-4M of bethanechol. Norepinephrine decreased basal tension both in normal and obstructed rats. After pre-treatment of propranolol, phenylephrine and norepinephrine did not show any increase of basal tension. CONCLUSIONS: Our results suggest that changes of adrenoceptors may be the underlying cause of bladder instability secondary to outflow obstruction as evidenced by significant inhibition of the tension of the detrusor muscle by alpha-1-adrenoceptor blocker(doxazosin but not by tamsulosin) only in obstructed rat bladder. These results also suggest that non-cholinergic components of bladder contraction are much more in obstructed than in normal bladder. It also can be said that doxazosin may have additional effects against bladder instability caused by BPH.