Partial Bladder Outlet Obstruction In Rats Research Articles

Sodium butyrate ameliorates erectile dysfunction through fibrosis in a rat model of partial bladder outlet obstruction.

In different animal models, a histone deacetylase (HDAC) inhibitor, sodium butyrate (NaBu) reduced inflammation, oxidative stress and fibrosis which were involved in the pathogenesis of erectile dysfunction (ED), but whether NaBu could improve ED in an experimental animal model of benign prostate hyperplasia (BPH) was not known. To investigate the preventive effect of NaBu on ED in a partial bladder outlet obstruction (PBOO) rat model. PBOO was induced by partial urethral obstruction. NaBu (20mg/kg/day) was administered orally to rats for 6 weeks after creation of PBOO. In vivo erectile responses, in vitro relaxation and contraction responses in cavernosal tissue were measured. Real-time polymerase chain reaction (RT-PCR) and Western blot were performed to determine the gene and protein expression. Inflammation, fibrosis, and localization of proteins were evaluated using histological techniques. HDAC activity and tumor necrosis factor (TNF)-α levels were measured in penile tissues. NaBu improved decreased intracavernosal pressure/mean arterial pressure, nitrergic and endothelium-dependent relaxation responses, and contractile responses to phenylephrine and electrical field stimulation in the PBOO group without affecting increased bladder weight. Increased endothelial nitric oxide synthase (eNOS), transforming growth factor (TGF)-β1, and nuclear factor kappa B (NF-κB) gene levels in PBOO group were ameliorated by NaBu treatment. The administration of NaBu to PBOO rats significantly increased neuronal NOS (nNOS) and decreased TGF-β1 protein expression. The nuclear/cytosolic ratio of NF-κB demonstrated a decrease in PBOO and all treatment groups compared to control. A significant increase in the nuclear-to-cytoplasmic ratio of nuclear factor erythroid 2-related factor 2 (Nrf2) after PBOO was reduced by the treatment. Both eNOS and inducible NOS (iNOS) protein expression, together with TNF-α levels did not differ in the penile tissue of all groups. In histological analysis, increased TGF-β1 protein expression and fibrosis, as well as decreased nNOS protein in PBOO, were reversed by the treatment. NaBu did not normalize moderate inflammation in obstructed rats. An increase in the HDAC activity in PBOO was significantly suppressed by NaBu. Inhibition of the HDAC activity by NaBu in penile tissue could ameliorate fibrosis-associated changes induced by PBOO. NaBu promotes recovery of erectile function, and also significantly prevents penile fibrosis and normalizes TGF-β1 and nNOS protein expression in a rat model of PBOO. The HDAC pathway may present a promising target to prevent ED in patients with BPH.

β-Adrenoceptor regulates contraction and inflammatory cytokineexpression of human bladder smooth muscle cells via autophagy under pathological hydrostatic pressure.

Abnormal intravesical pressure created by partial bladder outlet obstruction (PBOO) triggered the progression from chronic inflammation to fibrosis, initiating structural and functional alterations of bladder. To elucidate the underlying mechanisms of contraction and inflammatory response, we investigated the isolated human bladder smooth muscle cells (hBSMC) under pathological hydrostatic pressure (HP) mimicking the in vivo PBOO condition. hBSMCs were subjected to HP of 200 cm H2 O to explore the contraction and inflammatory cytokineexpression of hBSMC treated with β-adrenoceptors (ADRBs) and/or autophagy signaling pathway agonists and/or antagonists. We showed that pathological HP induced the release of the proinflammatory cytokines, including monocyte chemotactic protein-1, regulated upon activation normal T cell expressed and secreted factor, and interleukin-6. HP downregulated ADRB2 and ADRB3 expression, which was consistent with the results of the PBOO rat model. ADRB2 or autophagy activation repressed pathological HP-induced proinflammatory cytokineproduction. ADRB2, ADRB3 or autophagy activation ameliorated the HP-enhanced contraction. The increased contraction and autophagy activity by ADRB2 agonist under HP conditions were reversed by pretreatment with antagonists of adenosine monophosphate-activated protein kinase (AMPK). The present study provides evidence that the ADRB3 agonist suppresses hBSMC contraction under pathological HP conditions. Moreover, the ADRB2 agonist negatively regulates the contraction and inflammatory response of hBSMCs through AMPK/mTOR-mediated autophagy under pathological HP. These findings provide a theoretical basis for potential therapeutic strategies for patients with PBOO.

缝隙连接蛋白-43在膀胱出口部分梗阻的大鼠逼尿肌细胞膜中的表达

缝隙连接蛋白-43在膀胱出口部分梗阻的大鼠逼尿肌细胞膜中的表达

The Antimuscarinic Agent Tolterodine Regulates Bladder Extracellular Matrix in Partial Bladder Outlet Obstruction in Rats

Background/Aims: Antimuscarinic agents can delay the progression of bladder dysfunction caused by bladder outlet obstruction (BOO). To date, the relationship between muscarinic receptor activity and the bladder extracellular matrix (ECM) remains unclear. Thus, an animal model of partial BOO (PBOO) in female rats was established to explore the variation in bladder wall ECM proteins under PBOO conditions with antimuscarinic agent administration. Methods: Rats were randomly divided into three groups: sham, PBOO, and PBOO plus tolterodine. Picrosirius red staining was used to examine the smooth muscle and collagen content of bladder samples. Gene microarray and RT-PCR were performed to survey the expression of ECM proteins, receptors, and metabolism regulators in the rat bladder. Positive results were further evaluated by immunohistochemistry. Results: Picrosirius red staining showed that smooth muscle volume significantly increased in the PBOO and PBOO plus tolterodine groups (p < 0.05), while collagen significantly increased in the PBOO group (p < 0.05) but not in the PBOO plus tolterodine group. Gene microarray and RT-PCR revealed that none of the collagen subtypes exhibited significant changes after PBOO establishment and tolterodine administration. However, matrix metalloproteinases (MMPs) increased significantly in the PBOO plus tolterodine group (p < 0.05). Additionally, PBOO inhibited the expression of non-collagen ECM proteins in the rat bladder wall, while tolterodine induced the expression of non-collagen ECM proteins and ECM receptors. Conclusions: Tolterodine decreased the volume of collagen in PBOO rat bladder wall, possibly via MMPs, and regulated the expression of ECM proteins and receptors.

Enhanced expression of TWIK-related arachidonic acid-activated K+ channel in the spinal cord of detrusor overactivity rats after partial bladder outlet obstruction.

BackgroundDetrusor overactivity (DO) secondary to partial bladder outlet obstruction (PBOO) is closely associated with alteration of ion channels. The objective of this study is to investigate the expression of the TWIK-related arachidonic acid-activated K+ channel (TRAAK) in the L6-S1 spinal cord of DO rats after PBOO.MethodsFemale Sprague–Dawley rats undergoing PBOO surgery were screened for DO by cystometry. Sham-operated rats served as controls. The expression of TRAAK in the L6-S1 spinal cord was detected by real-time polymerase chain reaction, western blotting and immunohistochemistry.ResultsDO was successfully induced after chronic PBOO in rats, with an incidence rate of 62.5 %. Compared with sham-operated rats, the expression of TRAAK in the L6-S1 spinal cord of DO rats was significantly increased at the mRNA (1.886 ± 0.710 versus 0.790 ± 0.679, P < 0.05) and protein level (0.510 ± 0.087 versus 0.255 ± 0.107, P < 0.05). Immunohistochemical staining showed increased expression of TRAAK in the dorsal horn and ventral horn of the spinal cord.ConclusionsUpregulation of TRAAK was observed in the spinal cord of DO rats after chronic PBOO, which may exert a protective effect against DO by suppressing the excitability of neurons.

Sodium Tanshinone IIA Sulfonate Ameliorates Bladder Fibrosis in a Rat Model of Partial Bladder Outlet Obstruction by Inhibiting the TGF-β/Smad Pathway Activation.

Transforming growth factor (TGF)-β1 is known to play a pivotal role in a diverse range of biological systems including modulation of fibrosis in several organs. The precise role of TGF-β/Smad signaling in the progression of bladder fibrosis secondary to partial bladder outlet obstruction (PBOO) is yet to be conclusively. Using a rat PBOO model, we investigated TGF-β1 expression and exaimined whether sodium tanshinone IIA sulfonate (STS) could inhibit TGF-β/Smad signaling pathway activation and ameliorate bladder fibrosis. Forty-eight female Sprague-Dawley rats were randomly divided into three groups: sham operation group (n = 16), PBOO operation without STS treatment group (n = 16) and PBOO operation with STS treatment group (n = 16). Thirty-two rats underwent the operative procedure to create PBOO and subsequently received intraperitoneal injections of STS (10 mg/kg/d; n = 16) or vehicle (n = 16) two days after the surgery. Sham surgery was conducted on 16 rats, which received intraperitoneal vehicle injection two days later. In each of the three groups, an equal number of rats were sacrificed at weeks 4 and 8 after the PBOO or sham operation. The TGF-β/Smad signaling pathway was analyzed using western blotting, immunohistochemical staining and reverse transcriptase polymerase chain reaction (RT-PCR). One-way analysis of variance was conducted to draw statistical inferences. At 4 and 8 weeks, the expression of TGF-β1 and phosphorylated Smad2 and Smad3 in STS-treated PBOO rats was significantly lower than in the PBOO rats not treated with STS. Alpha smooth muscle actin (α-SMA), collagen I and collagen III expression at 4 and 8 weeks post PBOO was lower in STS-treated PBOO rats when compared to that in PBOO rats not treated with STS. Our findings indicate that STS ameliorates bladder fibrosis by inhibiting TGF-β/Smad signaling pathway activation, and may prove to be a potential therapeutic measure for preventing bladder fibrosis secondary to PBOO operation.

MP31-14 CHANGES IN APOPTOSIS RELATED PROTEINS IN THE BLADDER AFTER PARTIAL BLADDER OUTLET OBSTRUCTION RELIEF

You have accessJournal of UrologyBenign Prostatic Hyperplasia: Basic Research1 Apr 2015MP31-14 CHANGES IN APOPTOSIS RELATED PROTEINS IN THE BLADDER AFTER PARTIAL BLADDER OUTLET OBSTRUCTION RELIEF Ki Hak Song, Chong koo Sul, Yong gil Na, Jae sung Lim, Ju Hyun Shin, and Jong mok Park Ki Hak SongKi Hak Song More articles by this author , Chong koo SulChong koo Sul More articles by this author , Yong gil NaYong gil Na More articles by this author , Jae sung LimJae sung Lim More articles by this author , Ju Hyun ShinJu Hyun Shin More articles by this author , and Jong mok ParkJong mok Park More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2015.02.1369AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookTwitterLinked InEmail INTRODUCTION AND OBJECTIVES Partial bladder outlet obstruction (PBOO) induces prolonged bladder over-distension, leading to bladder dysfunction and structural alterations via induction of apoptosis. The aim of present study was to investigate sequential course of the apoptosis in bladder tissue, and changes of apoptosis related proteins in PBOO and subsequent relief. METHODS The study was conducted using 60 female Sprague-Dawley rats (body weight 250–300 g), divided into sham operated group (n=20), PBOO only (n=20), and PBOO group plus subsequent relief (n=20). PBOO rats were induced for 2 weeks, the obstruction has relived by removal of ligation after 2 weeks. After PBOO and relief surgery, urodynamic studies measuring contraction interval and contraction pressure were done. The tissues of rats were assessed by histologic anaylsis (H&E and TUNNEL stain) and expression of apoptosis related receptors (such as caspase-3, Erk, Jnk, P38, Bax, Bcl-2 and Survivin) have detected by RT-PCR and Western blotting. RESULTS Filling cystometry studies showed a significant decrease in contraction interval and increase in contraction pressure in the PBOO group. TUNNEL positive cells were significantly increased in PBOO group compared to sham operated group and decreased in PBOO relief group compared to PBOO group. On RT-PCR and Western blotting, expression of Bax, caspase-3, P38 and Jnk was significantly increased in PBOO group. But, expression of Erk, Bcl-2 was significantly decreased in PBOO group. The expression of Erk and Bcl-2 was significantly increased in PBOO relief group compared to PBOO group. CONCLUSIONS PBOO induced apoptosis of bladder tissue is associated with imbalance of MAPK pathways and apoptosis related protein. These results may also imply that pro-survival Erk kinase cascade is activated in response ischemic bladder injury and associated with initiation of bladder protection after PBOO. However, the mechanism of Survivin as anti-apoptotic factor in ischemic bladder tissue remains unclear. © 2015 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 193Issue 4SApril 2015Page: e361 Advertisement Copyright & Permissions© 2015 by American Urological Association Education and Research, Inc.MetricsAuthor Information Ki Hak Song More articles by this author Chong koo Sul More articles by this author Yong gil Na More articles by this author Jae sung Lim More articles by this author Ju Hyun Shin More articles by this author Jong mok Park More articles by this author Expand All Advertisement Advertisement PDF downloadLoading ...

Effect of short- and long-term sildenafil treatment on erectile dysfunction in rats with partial bladder outlet obstruction.

Lower urinary tract symptoms (LUTS) and erectile dysfunction (ED) are frequent problems in older men worldwide. We evaluated the effect of short- and long-term sildenafil treatment on erectile function in rats with surgically induced partial bladder outlet obstruction (PBOO). A total of 60 male Sprague-Dawley rats were randomized in five groups: (1) control (sham-operated); (2) PBOO for 3 weeks; (3) PBOO for 6 weeks; (4) sildenafil (1.5 mg/rat/day) treated PBOO for 3 weeks; and (5) sildenafil treated PBOO for 6 weeks. We assessed erectile function by measuring intracavernous pressures (ICP), mean arterial pressure (MAP) and total ICP after cavernous nerve stimulation. Corpus cavernous smooth muscle (CCSM) strips were isolated and evaluated for relaxation responses using organ-bath preparation. Neuronal nitric oxide synthase (nNOS) expression was determined immunohistochemically. Experimental PBOO at 3 and 6 weeks showed decreased erectile response based on ICP/MAP ratio, total ICP and decreased expression of nNOS, which returned to normal after prolonged daily treatment with sildenafil. CCSM strips from PBOO rats displayed reduced relaxation responses to both electrical field stimulation (EFS) and acetylcholine (ACh) as well as nNOS enzyme intensity when compared to untreated PBOO group, which was reversed by treatment with sildenafil for 6 weeks. Daily sildenafil treatment prevents development of ED in PBOO rats in a time dependent manner. Further studies are needed to explore the effectiveness of sildenafil in patients with BPH/LUTS in association with ED.

Urine uromodulin estimation in partial bladder outlet obstruction and cyclophosphamide-induced haemorrhagic cystitis models in rats.

Uromodulin (UMOD) is a glycoprotein excreted by the thick ascending limb of the Henle's loop and distal convoluted tubule cells, playing various, yet still unclear roles. An abnormal urinary UMOD excretion is observed in many pathophysiological conditions. The aim of our study was to assess urine UMOD excretion in experimental partial bladder outlet obstruction (PBOO), reflecting BPH in humans, and in cyclophosphamide-induced haemorrhagic cystitis (CP-HC). PBOO and CP-HC rats and two appropriate control groups were studied. The PBOO model was surgically induced by partial proximal urethral obstruction and CP-HC by four i.p. cyclophosphamide administrations (every two days). 24-hour urine collections were performed in both PBOO (on 3rd, 7th, 12th and 15th day after surgery) and CP-HC rats (on 1st, 3rd, 5th and 7th day). UMOD was determined with the ELISA method. Both 24-hour urinary UMOD excretion and urinary UMOD concentrations were determined. In the overall assessment, PBOO rats were characterized by decreased mean urinary UMOD concentration. However, as the urine volume, except for transient drop on 3rd day following PBOO operation, was steadily increasing, the daily urinary uromodulin excretion did not differ from the control one. Contrary to PBOO, CP-HC rats demonstrated mean urinary concentration similar to that of the control rats, while their 24hr UMOD excretion in urine was almost doubled due to urine volume increase (from 1.6 up to almost 3 fold). The highest UMOD urinary output was observed after the 3rd and 4th doses of cyclophosphamide. A reduced urinary UMOD excretion in early PBOO phase may be considered as a marker of distal tubular cells damage due to incomplete bladder emptying and increased pressure retrograding to distal tubules. This effect disappears with structural, adaptive histological changes of the bladder wall leading to an improved voiding. In CP-HC animals, the elevated urinary UMOD level may be associated with complex inflammatory response due to the cytotoxic CP action. UMOD assessment in this model may reflect renal and urological toxicity as UMOD excretion rises with the cumulative cyclophosphamide dose.

Effect of ovariectomy, 17-beta estradiol, and progesterone on histology and estrogen receptors of bladder in female partial bladder outlet obstruction rat model

The aim of this study was to investigate the effect of bilateral ovariectomy (OVX), 17-beta estradiol (E2), and progesterone (P4) on the histology and estrogen receptor (ER) expression of the bladder using a female partial bladder outlet obstruction (pBOO) rat model. A total of 60 female Sprague-Dawley rats were evenly assigned into six groups of 10 each. Group A served as the control. Groups B-F underwent induced pBOO. Groups C-F underwent OVX. Groups D-F were given E2 (0.1 mg/kg/day), Group E was given P4 (1 mg/kg/day), and Group F was given P4 and dehydroepiandrosterone (DHEA) (300 μg/kg/day) by an Alzet pump. Four weeks later, serum E2 and P4 levels were evaluated. Each rat was anesthetized and the urinary bladder was removed for weighing and histological study. Expression of ER-β was not significantly different between the control group and the other study groups. pBOO was shown to increase both bladder weight and detrusor muscle thickness. OVX had an additive effect to BOO on increased blood vessel density in the bladder. E2 was shown to increase blood vessel density, while P4 supplementation decreased blood vessel density. DHEA did not cause any significant effects on blood vessel density. Hormone therapy did not change the expression of ER in bladder outlet obstruction. Estradiol stimulated the increased angiogenesis of the bladder detrusor but P4 decreased the angiogenesis of the bladder detrusor. DHEA had no effect on the bladder detrusor.

Expression and electrophysiological characteristics of P2X3 receptors in interstitial cells of Cajal in rats with partial bladder outlet obstruction

WHAT'S KNOWN ON THE SUBJECT? AND WHAT DOES THE STUDY ADD?: In the urinary bladder, histological studies suggest a network of functionally connected interstitial cells of Cajal (ICCs) are located between the urothelium and sensory nerve endings, which might transfer signals directly between them. Purinergic P2X3 receptors may play roles in the micturition reflex pathway, and its expression profiles in ICCs could be altered in urinary bladder dysfunction. The present experiments showed a novel time-dependent P2X3 receptor up-regulation in ICCs in an experimental rat model of partial bladder outlet obstruction. To investigate the expression and electrophysiological characteristics of purinergic P2X3 receptors in interstitial cells of Cajal (ICCs) at different time points after partial bladder outlet obstruction (PBOO) in rats. In all, 48 female Sprague-Dawley rats were randomly divided into four groups: 4, 6 and 8 week PBOO groups and sham-operated controls. At 4 weeks after surgery, cystometry was performed to investigate bladder function in vivo. Subsequently, the rats were humanely killed at 4, 6 or 8 weeks and the bladders were harvested for measurements. P2X3 expression in ICCs of bladder was investigated by immunofluorescent staining. The level of P2X3 mRNA was detected by reverse transcription-polymerase chain reaction (RT-PCR). Inward currents in corresponding ICCs after PBOO were investigated electrophysiologically. Cystometrography showed a valid increase in maximum detrusor pressure in rats subjected to PBOO. The bladder weight in the PBOO group was significantly higher than that in the control group. In contrast to sham rats, there was a significant increase in the intensity of P2X3 staining in the ICCs in all PBOO groups. C-kit labelled isolated ICCs were strongly stained with the P2X3 antibody. RT-PCR showed that the expression of P2X3 mRNA was significantly up-regulated at 4, 6 and 8 weeks in the ICCs from the PBOO rats. In the ICCs, the mean peak amplitude of inward currents was significantly increased in the PBOO groups compared with the control group. The expression of P2X3 receptors showed a time dependent up-regulation in the ICCs of the bladder in rats with PBOO. PBOO induced the potentiation of P2X3 receptors function, as evidenced by α, β-methylene ATP-enhanced inward currents in the ICCs of the rat bladder.

Effect of doxazosin on expression of eNOS in rat kidney in the presence of partial bladder outlet obstruction

The role of nitric oxide in the pathogenesis of renal injury has begun to be appreciated. We therefore designed this study to demonstrate the relationship between endothelial nitric oxide synthase (eNOS) expression and doxazosin in the kidneys of rats with surgically created partial bladder outlet obstruction (BOO), to further understand the role of doxazosin in the prevention of renal parenchymal damage by partial BOO. A total of 35 adult female Wistar rats, mean weight 250 g, were randomly allocated to 3 experimental groups: group1, sham-operated (n=10); group 2, partial BOO group (n=14) and group 3, partial BOO group treated with doxazosin (n=11). Partial BOO in rats was surgically induced. Results were assessed by eNOS immunohistochemistry. eNOS staining in kidneys in group 1 (16.45 ± 1.63) was significantly higher than in group 2 (5.09 ± 0.61) (p<0.05). After 15 days of doxazosin treatment in addition to partial BOO (group 3), eNOS staining in the kidney (11.80 ± 1.63) was significantly higher than in group 2 (5.09 ± 0.61) (p<0.05). In samples taken after 15 days of doxazosin treatment in addition to partial BOO, eNOS staining in kidneys (11.80 ± 1.63) was lower than in the sham-operated group (16.45 ± 1.63), but the difference was not significant (p>0.05). These findings may provide insight into the beneficial and restorative effects of α(1)-adrenoceptor antagonists on eNOS expression in the kidney, when used to treat symptoms of benign prostate hyperplasia and hypertension.

Blebbistain, a Myosin II Inhibitor, as a Novel Strategy to Regulate Detrusor Contractility in a Rat Model of Partial Bladder Outlet Obstruction

Partial bladder outlet obstruction (PBOO), a common urologic pathology mostly caused by benign prostatic hyperplasia, can coexist in 40–45% of patients with overactive bladder (OAB) and is associated with detrusor overactivity (DO). PBOO that induces DO results in alteration in bladder myosin II type and isoform composition. Blebbistatin (BLEB) is a myosin II inhibitor we recently demonstrated potently relaxed normal detrusor smooth muscle (SM) and reports suggest varied BLEB efficacy for different SM myosin (SMM) isoforms and/or SMM vs nonmuscle myosin (NMM). We hypothesize BLEB inhibition of myosin II as a novel contraction protein targeted strategy to regulate DO. Using a surgically-induced male rat PBOO model, organ bath contractility, competitive and Real-Time-RT-PCR were performed. It was found that obstructed-bladder weight significantly increased 2.74-fold while in vitro contractility of detrusor to various stimuli was impaired ∼50% along with decreased shortening velocity. Obstruction also altered detrusor spontaneous activities with significantly increased amplitude but depressed frequency. PBOO switched bladder from a phasic-type to a more tonic-type SM. Expression of 5’ myosin heavy chain (MHC) alternatively spliced isoform SM-A (associated with tonic-type SM) increased 3-fold while 3’ MHC SM1 and essential light chain isoform MLC17b also exhibited increased relative expression. Total SMMHC expression was decreased by 25% while the expression of NMM IIB (SMemb) was greatly increased by 4.5-fold. BLEB was found to completely relax detrusor strips from both sham-operated and PBOO rats pre-contracted with KCl, carbachol or electrical field stimulation although sensitivity was slightly decreased (20%) only at lower doses for PBOO. Thus we provide the first thorough characterization of the response of rat bladder myosin to PBOO and demonstrate complete BLEB-induced PBOO bladder SM relaxation. Furthermore, the present study provides valuable evidence that BLEB may be a novel type of potential therapeutic agent for regulation of myogenic and nerve-evoked DO in OAB.

Regulation of Connexin 43 by Basic Fibroblast Growth Factor in the Bladder: Transcriptional and Behavioral Implications

Basic fibroblast growth factor is a candidate causative factor of detrusor overactivity in bladder outlet obstruction cases through up-regulation of the gap junction protein connexin 43. We addressed the transcriptional and behavioral implications of this axis. Cx43 and Cx45 mRNA expression was assessed by real-time reverse transcriptase-polymerase chain reaction in the bladder of a rat bladder outlet obstruction model and in cultured rat bladder smooth muscle cells with and without basic fibroblast growth factor treatment. Involvement of the extracellular signal regulated kinase 1/2-activator protein-1 pathway was evaluated by immunofluorescence study and a promoter-reporter assay in bladder smooth muscle cells. The effect of basic fibroblast growth factor on micturition behavior was measured in unrestrained rats under a 12-hour light/dark cycle using a controlled release system from gelatin hydrogels fixed on the bladder. The expression of extracellular signal regulated kinase 1/2 and connexin 43 protein was assessed by Western blotting of rat bladder protein. Cx43 but not Cx45 mRNA expression was increased in the bladder of the obstruction model and in bladder smooth muscle cells treated with basic fibroblast growth factor. The mitogen-activated and extracellular signal-regulated kinase kinase inhibitor PD98059 blocked the stimulatory effect of basic fibroblast growth factor on connexin 43 protein expression and promoter activity, which was also decreased by mutation or deletion of an activator protein-1 cis-element of the connexin 43 promoter. In vivo application of basic fibroblast growth factor on the bladder increased urinary frequency during the latter half of the dark phase, ie the late active phase of rats (F = 5.1, 2-way ANOVA p <0.05). The expression of phospho-extracellular signal regulated kinase 1/2 and connexin 43 protein was increased in the bladder. The extracellular signal regulated kinase 1/2-activator protein-1-connexin 43 axis could be a potential therapeutic target for increased urinary frequency.

Role of Nitric Oxide Synthase in Bladder Pathologic Remodeling and Dysfunction Resulting From Partial Outlet Obstruction

To investigate the relationship between nitric oxide synthase (NOS) and oxidative stress and pathologic remodeling in the partial obstructed bladder of a rat model. We surgically established partial bladder outlet obstruction (PBOO) in 2 groups of rats and allowed it to persist for 3-6 weeks. Normal and sham-operated rats served as the controls. Each group contained 6 rats for a total of 24 rats. Cystometry was used to evaluate the bladder function. The bladders were removed, and histopathologic measurements were performed to evaluate bladder hypertrophy and fibrosis and NOS immunolocalization. Biochemical measurements were used to evaluated NOS mRNA and activity and the oxidative stress level. The obstructed rats experienced significant increases in bladder weight, muscle hypertrophy, and deposits of collagen fibers compared with the normal and sham-operated groups. PBOO debilitated bladder contractibility, increased the residual urine volume and voiding interval, decreased the voiding volume, and caused poor bladder emptying, with an increased residual urine volume and decompensated bladder in the PBOO rats at 6 weeks. The elevation in malondialdehyde and reduction in superoxide dismutase activity in the PBOO rats suggested that oxidative stress injury occurred in the obstructed bladder. Lower inducible NOS and endothelial NOS (eNOS) mRNA expression was demonstrated through quantitative polymerase chain reaction. In particular, eNOS was significantly downregulated in the PBOO rats compared with the normal and sham-operated rats. The normal and PBOO bladder tissues did not express detectable levels of neuronal NOS mRNA or exhibit neuronal NOS immunoreactivity. The total NOS activity had decreased progressively in the PBOO groups in conjunction with the significantly decreased eNOS activity compared with that in the normal and sham-operated groups. These findings suggest that decreases in NOS activity and expression (mainly of eNOS) concomitant with increases in reactive oxygen species generation represent the underlying pathogenic mechanism of obstructed bladder remodeling and dysfunction.

Chronic partial bladder outlet obstruction does not impair erectile function in male rats

To evaluate, in a well-controlled study, the effect of surgically induced partial bladder outlet obstruction (PBOO) on male erectile function in a rat model. PBOO was created in 17 adult male Sprague-Dawley rats by partial ligation of the proximal urethra. Sham-operated and PBOO rats were evaluated for urodynamic and erectile function at 4-8 weeks after surgery. Erectile responses to electrical field stimulation (EFS) to the major pelvic ganglion, and to erectogenic agents (1,1-diethyl-2-hydroxy-2-nitroso-hydrazine, DEA-NO, and Y-27632) were evaluated and the area under the curve (AUC, a product of the intracavernous pressure and duration) was used to denote the erectile response. Experimental PBOO in rats significantly increased the mean (sem) bladder weight, to 256 (25) mg in PBOO rats vs 123 (24) mg in sham controls, and the voiding frequency to 1.01 (0.1) voids/min vs 0.72 (0.14) voids/min in sham controls (P < 0.05). There was no significant difference between the erectile response to EFS, with a mean AUC in sham control rats at 1.5, 3.0 and 4.5 V of 2603 (372), 3200 (332) and 3357 (166), respectively, vs 2273 (183), 3794 (211) and 4177 (306) in PBOO rats (P > 0.05); or to the erectogenic agents, the AUC for DEA-NO being 9000 (975) in PBOO rats vs 13 201 (2756) in sham controls, and the AUC for Y-27 632 being 44 915 (2462) and 45 907 (7408), respectively (P > 0.05). There was greater immunoreactivity to RhoA in bladder and penile tissues of PBOO than control rats. PBOO does not affect erectile function in rats. Additional mechanisms or pathways might be involved in lower urinary tract symptom-related erectile dysfunction in humans.

Changes of bladder activity and connexin 43-derived gap junctions after partial bladder-outlet obstruction in rats

We investigated changes of vesical gap junctions in relation to changes of the micturition reflex in rats with partial bladder-outlet obstruction (BOO). A total of 66 female Sprague-Dawley rats were divided into six groups: sham operation (control); 3, 14, and 28 days after BOO; and 3 and 28 days after relief of BOO lasting for a three-day period. Under urethane anesthesia, isovolumetric cystometry was performed on each group. Expression of mRNA for the gap-junction protein connexin 43 (Cx43) in the bladder was measured in each group. Immunohistochemistry using Cx43 antibody was also performed on the bladder after BOO. The interval between bladder contractions was shorter in all of the other groups than in the control group. Expression of Cx43 mRNA was increased 3, 14, and 28 days after BOO (the peak increase was twofold), and three days after the relief of BOO, but it returned to the control level by 28 days after relief of BOO. Histologically, smooth muscle hypertrophy was detected in the bladder after BOO and punctate staining of the smooth muscle by Cx43 antibody increased after BOO. These results suggest that partial BOO produces detrusor overactivity that may depend on increased intercellular communication via gap junctions in the bladder. Relief of BOO led to a decrease of Cx43 mRNA, but detrusor overactivity persisted in the chronic phase, suggesting a reversible change of vesical gap junctions and an irreversible change of bladder activity after BOO.

Application and Limitations of Awake Cystometry in Sprague-Dawley Rats with Partial Bladder Outlet Obstruction as a Model of Overactive Bladder or Obstruction

Purpose: Partial bladder outlet obstruction (PBOO) in rats leads to changes in bladder function, such as obstruction and detrusor overactivity (DO). The aim of our study was to observe factors essential for the objective descriptions of PBOO rats as an overactive bladder model as well as an obstruction model under awake cystometry. We also aimed to investigate the urodynamic effects of PBOO objectively in view of DO-related parameters as well as conventional pressure and volume-related parameters. Materials and Methods: PBOO was produced in 10 female Sprague-Dawley rats by ligating the proximal urethra over a 0.9 mm metal rod; 10 sham-operated rats were used as controls. Intravesical pressure (IVP) was recorded via an open catheter in the bladder, and intraabdominal pressure (IAP) via an intraabdominal balloon catheter. Continuous cystometry was performed 2 weeks after the PBOO procedure. Conventional and newly developed DO-related urodynamic parameters were investigated. Results: PBOO led to a significant increase in bladder weight. Three rats showed the picture of decompensated bladder and were excluded from the analysis. The obstructed group showed some increased pressure- and volume-related parameters. They showed a DO frequency of 1.50.3/min, but the sham group did not. Conclusions: Our results showed that bladder decompensation can happen after PBOO, and we need to describe those exclusions accurately in reports. In conscious PBOO rats, simultaneous registration of IAP and IVP is needed for accurate investigations of DO, because PBOO can lead to DO as well as bladder hypertrophy.

Alfuzosin attenuates erectile dysfunction in rats with partial bladder outlet obstruction

To determine how partial bladder outlet obstruction (PBOO) in a rat model affects erectile function, and whether an uroselective alpha1-adrenoceptor antagonist, alfuzosin (Sanofi-Aventis, Paris, France) attenuates any erectile dysfunction (ED). Adult male Sprague-Dawley rats (120) were randomized into four groups: 1, sham-operated; 2, alfuzosin-treated; 3, PBOO; and 4, alfuzosin-treated with PBOO. Groups 3 and 4 were subjected to PBOO for 6 weeks by ligation of the urethra, while groups 2 and 4 rats received daily oral alfuzosin (10 mg/day) for 6 weeks. In vivo erectile responses were monitored by evaluating ratios of intracavernosal pressure (ICP)/mean arterial pressure, and total ICP (area under the curve). Organ-bath studies were performed on corpus cavernosum smooth muscle (CCSM) strips. Nitric oxide synthase (NOS) expression was determined immunohistochemically (IHC) for neuronal (n)NOS and by Western blot analysis for endothelial (e) and inducible (i) NOS protein. Rats with PBOO showed lower erectile responses than controls. Maximum electrical field stimulation-mediated and endothelium-dependent acetylcholine-induced relaxations and contractile responses to phenylephrine were significantly reduced in CCSM strips from the PBOO group. The NO donor sodium nitroprusside completely relaxed CCSM from rats in all groups. IHC analyses showed decreased expression of nNOS in PBOO groups compared with controls; by contrast, protein expression of eNOS and iNOS was increased. Alfuzosin-treatment partially attenuated functional and molecular changes in penises of PBOO rats. Rats with PBOO show ED, most likely due to altered NOS expression and NO bioavailability. The alpha-adrenoreceptor antagonist alfuzosin reversed this ED by altering sympathetic tone, increasing NO-induced relaxation and augmenting blood flow in the penis. This study suggests a rationale for further clinical trials using combinations of alpha-adrenoceptor antagonists and phosphodiesterase-5 inhibitors in patients with ED and lower urinary tract symptoms.

Effect of partial bladder outlet obstruction on detrusor compliance, excitability and contractility in rats

Partial bladder outlet obstruction (PBOO) is believed to change the functions of the detrusor, and can lead to an overactive detrusor (OD). The aim of this study was to investigate changes in bladder compliance, excitability and contractility after PBOO in rats. PBOO was performed for 6 weeks in 20 Wistar rats, 13 of which (OD group) had an OD and seven of which (non-OD group) did not. Simultaneously, 10 rats that underwent sham operations (control group) were also studied. Bladder compliance and cystometric capacity were identified in vivo, but bladder compliance was detected without elimination of bladder capacity. Isolated bladder smooth muscle strip (BSMS) was dissected to determine excitability and contractility. After 6 weeks of PBOO, cystometric capacity and compliance were significantly higher than those in the control group. Compliance was 0.170+/-0.029 and 0.149+/-0.042 ml/cmH2O in the OD and non-OD groups, respectively, compared to 0.037+/-0.017 ml/cmH2O in the control group. The corresponding cystometric capacities were 3.66+/-0.490, 3.08+/-0.590 and 1.14+/-0.225 ml. The excitability in the OD group increased significantly compared to that in the non-OD and control groups. The tension threshold for BSMS contraction was lower in the OD group, and BSMS contracted more frequently at the same tension. The contractility of the BSMS in the OD group decreased significantly compared to that in the non-OD and control groups. PBOO can cause a higher cystometric capacity and compliance. After PBOO, there is a chance that an OD may develop. When this occurs, the detrusor excitability increases and contractility decreases.