The influence of ovariectomy and estrogen replacement on voiding patterns and detrusor muscarinic receptor affinity in the rat

Investigating the Impact of Estrogen Levels on Voiding Characteristics, Bladder Structure, and Related Proteins in a Mouse Model of Menopause-Induced Lower Urinary Tract Symptoms

Lower urinary tract symptoms (LUTS) are common in postmenopausal women. These symptoms are often linked to decreased estrogen levels following menopause. This study investigated the relationship between estrogen levels, alterations in bladder tissue structure, bladder function, and the incidence of urinary frequency. An age-appropriate bilateral ovariectomized mouse model (OVX) was developed to simulate conditions of estrogen deficiency. Mice were divided into three groups: a sham-operated control group, OVX, and an estradiol-treated group. The assessments included estrogen level measurement, urination frequency, cystometry, histological analysis, immunofluorescence staining, and real-time quantitative PCR. Additionally, we quantified the expression of the mechanosensitive channel proteins Piezo1 and TRPV4 in mouse bladder tissues. Lower estrogen levels were linked to increased voiding episodes and structural changes in mouse bladder tissues, notably a significant increase in Collagen III fiber deposition. There was a detectable negative relationship between estrogen levels and the expression of Piezo1 and TRPV4, mechanosensitive proteins in mouse bladder tissues, which may influence voiding frequency and nocturia. Estrogen treatment could improve bladder function, decrease urination frequency, and reduce collagen deposition in the bladder tissues. This study explored the connection between estrogen levels and urinary frequency, potentially setting the stage for novel methods to address frequent urination symptoms in postmenopausal women.

Seasonal variations in overactive bladder drug prescription rates in women: a nationwide population-based study

PURPOSE

Colder seasons can aggravate lower urinary tract symptoms, especially an overactive bladder (OAB). This aspect has been extensively studied in men and rarely in women. We investigated whether colder seasons influence OAB-drug prescription rates (OAB-DPRs) in women.

METHODS

Women aged > 18 years were selected from the Korean Health Insurance Review and Assessment Service-National Patient Sample data between 2012 and 2016. OAB-DPR was calculated according to age and seasonal groups. The prescription rates in summer (June, July, and August) and winter (January, February, and December) months were compared. Sub-analysis was performed according to age group.

RESULTS

In total, 3,061,343 adult women were included. The overall OAB-DPR was 3.75% (114,940/3,061,343). Overall OAB-DPRs in summer and winter were 1.41% (43,090/3,061,343) and 1.54% (47,038/3,061,343), respectively (p < 0.001). Seasonal variations in OAB-DPRs differed by age group (p < 0.001): OAB-DPRs were significantly lower in winter than in summer months in women aged < 50 years (odds ratio 0.942; 95% confidence interval 0.918-0.967; p < 0.001), but significantly higher in winter than in summer months in women aged ≥ 50 years (odds ratio 1.153; 95% confidence interval 1.135-1.171; p < 0.001).

CONCLUSION

In this study, a correlation was noted between OAB-DPR and seasons. OAB-DPRs were higher in the summer in women aged < 50 years and higher in the winter in women aged ≥ 50 years. Our findings suggest that female hormonal status may be involved in the contradictory effect of seasons on OAB symptoms.

Influence of ovariohysterectomy and deslorelin acetate on the spontaneous activity of the rabbit urinary bladder in vitro

Lower urinary tract symptoms are not only a serious health problem but also a substantial sociologic issue affecting human beings and companion animals. Estrogen deficiency is considered an etiologic factor of urinary incontinence in postmenopausal women and spayed female dogs. However, insufficient effectiveness of hormonal therapy has caused an intensive search for new therapeutic options. GnRH analogs have positive clinical effects in neutered female dogs suffering from incontinence, but the mechanism of action is not known. The aim of our study was to determine the effect of long-acting deslorelin acetate on the spontaneous activity of urinary bladder sections from a rabbit model of long-term estrogen deprivation. The study was conducted on 21 female New Zealand White rabbits divided into the following groups: control group, ovariohysterectomized (OHX) group, and ovariohysterectomized group given a deslorelin acetate implant. Urinary bladders were excised immediately after sacrifice, and the spontaneous activity of dorsal and ventral strips of the bladder body was examined in organ bath chambers. The amplitude and frequency of the spontaneous contractions were evaluated. Most of the sections developed spontaneous activity. Ovariohysterectomy caused a decrease in the amplitude of spontaneous contractions of the tissues obtained only from the dorsal part of the bladder body. After OHX, the frequency was higher compared with the control group in both parts of the bladder. Deslorelin acetate did not significantly affect the spontaneous contraction amplitude but caused a decrease in the frequency in the dorsal and ventral parts of the bladder. In conclusion, long-term changes in the levels of hormones and other regulatory substances associated with the reproductive system are related to altered spontaneous activity of the urinary bladder, which may impact the symptoms of urgency and incontinence appearing in women after menopause and in female animals after gonadectomy. However, long-acting deslorelin acetate partially reverses the effect of OHX on the spontaneous activity of the bladder. This process might underlie the positive effects of GnRH analogs in incontinent spayed female dogs.

Changes of muscarinic receptors and connexin-43 expression as a mechanism of overactive bladder in ovariectomized rats

PURPOSE

After menopause, the bladder is known to become overactive. To investigate the mechanisms involved in these changes, we examined the muscarinic receptors M2, M3 and gap junction protein connexin-43 in an ovariectomized rat bladder.

METHODS

Twenty 10-week-old female SD rats were used. Ten rats were ovariectomized, (Ovx group) and 10 rats received a sham operation (Con group). Four weeks after the operation, urodynamic tests were performed to verify overactive bladder, and the animals were killed. The body, bladder and uterus weights were measured. The bladder specimens were prepared for immunohistochemical staining for muscarinic receptors M2, M3 and connexin-43. Western blotting was also used for the same protein measurement (M2, M3 and connexin-43). A t test with a p value of 0.05 was considered significant, and SPSS 12.0 for Windows was used to analyze the data.

RESULTS

The mean body weight of the Ovx group (315.8 ± 18.1 g) was heavier than the Con group (270.0 ± 23.6 g) (p = 0.009). The mean uterus weight of the Ovx group (260.4 ± 186.8 g) was lighter than the Con group, (600.6 ± 175.9 g) (p = 0.028) and the mean bladder weight of the Ovx group (80.2 ± 15.9 g) was lighter than the Con group (97.4 ± 10.6 g) (p = 0.041). The mean bladder contraction of the Ovx group (5.5 ± 2.3/10 min) was more frequent than that of the Con group (3.2 ± 2.8) (p < 0.05). The expressions of M2 and M3 were not different between the Ovx and the Con group, but the expression of connexin-43 in the Ovx group was more intense than in the Con group in immunohistochemical staining. These findings were also confirmed by Western blotting results.

CONCLUSIONS

Ovariectomized rats showed frequent bladder contraction and increased connexin-43 expression without changes in M2 and M3 receptor expression. These results imply that ovariectomy-induced overactive bladder may be due to an altered gap junction protein function rather than muscarinic receptor modification.

[TECAR therapy for Peyronie’s disease: a phase-one prospective study. Great evidence in patients with erectile dysfunction]

Our phase-one prospective study wants to evaluate the safety and tolerability of TECAR therapy in the treatment of Peyronie’s disease. From June 2011 to September 2012 we enrolled 70 patients. Each patient had been previously subjected to andrological examination, to a questionnaire for the evaluation of IPP and ED, and the SF-36 (V1) for the evaluation of the general state of health. The evaluation of pain was made using the VAS scale of pain. Every patient was subjected to TECAR treatment of the fibrotic plaque (both in resistive mode and in capacitive mode) for a total of three sessions carried out on consecutive days. We recorded a good compliance by patients; none of them reported side effects. Pain was decreased by the technique in 80% of the cases.The whole sample completed the study. Surprisingly enough those patients who complained also of erectile dysfunction, reported an improvement in sexual potency.

[Role of estrogens in lower urinary tract physiology and physiopathology]

GOAL

The aim was to review the literature on estrogens and lower urinary tract.

MATERIAL

A review of literature through the PubMed library until December 31, 2012 was carried out using the following keywords: lower urinary tract, bladder, urethra, nervous central system, innervation, female, women, estrogen, estradiol, urogenital atrophy, urinary incontinence, overactive bladder, urinary tract infection.

RESULTS

On the bladder, estrogens are involved in the trophicity, vascularisation, alpha-adrenergic, cholinergic and muscarinic receptor density, detrusor contractility and inflammation. On the urethra, they impact vascularisation, contractility, urethral pulse and tone, anatomical and functional length. On the neurological control, they act on capsaicin-sensitive afferent fibres, neurological regeneration, nerve growth factor expression and viscerovisceral sensitisation.

CONCLUSION

Estrogens play a major role on the lower urinary tract physiology and physiopathology both on the urethra and the bladder.

Neuroprotection of green tea catechins on surgical menopause-induced overactive bladder in a rat model

OBJECTIVE

A rat model of ovariectomy-induced voiding dysfunction has been established, which mimicked the urge incontinence in postmenopausal women. Previous studies have identified strong anti-inflammatory/antioxidant properties of green tea and its associated polyphenols. The aim of this study was to evaluate whether the green tea extract, epigallocatechin gallate (EGCG), could prevent an ovariectomy-induced overactive bladder.

METHODS

The study included 48 female Sprague-Dawley rats, which were divided into four groups. After bilateral ovariectomy during the following 6-month period, 12 rats received an intraperitoneal injection of saline, 24 rats received either a low-dose (1 μM kg(-1) d(-1)) or a high-dose (10 μM kg(-1) d(-1)) EGCG intraperitoneal injection. The sham group consisted of twelve rats that were not ovariectomized. In vivo isovolumetric cystometrograms were performed in all groups before the animals were euthanized. The immunofluorescence study used neurofilament stains to evaluate intramural nerve damage. Western immunoblots and real-time polymerase chain reaction were performed to determine M2 and M3 muscarinic cholinergic receptors (MChRs) at both protein and messenger RNA (mRNA) expressions.

RESULTS

Long-term ovariectomy significantly increased non-voiding contractions, whereas treatment with EGCG significantly attenuated the frequency of non-voiding contractions. Ovariectomy significantly decreased the numbers of neurofilament and increased M2 and M3 MChR protein and mRNA expressions. Treatment with EGCG restored the amount of neurofilament staining and decreased M2 and M3 MChR protein and mRNA overexpressions.

CONCLUSIONS

This study confirmed that ovary hormone deficiency induced overactive bladder dysfunction via intramural nerve damage and muscarinic receptor overexpression. EGCG prevented ovariectomy-induced bladder dysfunction through neuroprotective effects in a dose-dependent fashion.

Green tea catechins decrease oxidative stress in surgical menopause-induced overactive bladder in a rat model

What's known on the subject? and What does the study add? Ovary hormone deficiency and the age-related changes in post-menopausal women are subjected to a number of urological dysfunctions, including overactive bladder syndrome. Green tea is a popular healthy drink worldwide and its extract catechin has strong anti-inflammatory and antioxidant properties. EGCG, the major type of catechin, is an antioxidant polyphenol flavonoid isolated from green tea. EGCG supplement could prevent ovariectomy-induced bladder dysfunction in a dose-related manner through its anti-oxidant, anti-fibrosis and anti-apoptosis effects.

OBJECTIVE

To evaluate whether green tea extract, epigallocatechin gallate (EGCG), could prevent ovariectomy-induced overactive bladder (OAB) and to investigate its antioxidant, anti-apoptotic and anti-fibrosis effects.

MATERIALS AND METHODS

In all, 48 female Sprague-Dawley rats were divided into four groups. After bilateral ovariectomy, the first group served as the ovariectomy control, the second group received EGCG 1 µM/kg daily i.p. injection after ovariectomy surgery, and the third group received EGCG 10 µM/kg daily i.p. injection. The fourth group was taken as the sham without ovariectomy surgery. The rats were killed after 6 months after ovariectomy surgery. Cystometrograms were performed for the measure of bladder overactivity. Terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling (TUNEL) assay was used to evaluate apoptotic cells. Western immunoblots were performed to determine the expressions of inflammatory markers, apoptosis-associated proteins and oxidative stress markers.

RESULTS

Long-term ovariectomy significantly increased non-voiding contractions and decreased bladder compliance. Treatment with EGCG significantly increased bladder compliance and diminished non-voiding contractions. Ovariectomy significantly increased apoptotic cells and enhanced interstitial fibrosis in bladders. The expression of caspase-3 significantly increased, while that of Bcl-2 notably decreased after ovariectomy. Inflammatory and fibrosis markers, TGF-β, fibronectin and type I collagen expressions were significantly increased after 6 months of ovariectomy surgery. Treatment with EGCG significantly decreased TGF-β and type I collagen expressions. Oxidative stress markers, nitrotyrosine and protein carbonylation levels were significantly increased in the ovariectomy group. EGCG could attenuate this oxidative damage in dose-dependent fashion.

CONCLUSIONS

Ovariectomy increased oxidative damage, enhanced voiding frequency and decreased bladder compliance. EGCG could restore ovariectomy-induced bladder dysfunction in a dose-dependent fashion through antioxidant, anti-fibrosis and anti-apoptosis effects.

Dietary phytoestrogens maintain contractile responses to carbachol with age in the female rat isolated bladder

AIMS

Development of urinary incontinence, for many women, occurs following menopause. Dietary phytoestrogens consumed over the long term may affect the contractile function and maintenance of the urinary bladder in post menopausal women. This study examined the muscarinic receptor mediated contractile responses in the rat isolated bladder in response to ovariectomy and long term dietary phytoestrogen consumption.

MAIN METHODS

Ovariectomised or sham-operated female Wistar rats (8 weeks) were fed either normal rat chow (soy, phytoestrogens) or a non-soy (phytoestrogen free) diet. Bladders were dissected from rats at 12, 24 and 52 weeks of age and placed in 25 ml organ baths filled with McEwans solution.

KEY FINDINGS

The contractile response to carbachol, in 12 week old female rats did not change as a result of dietary phytoestrogens or ovariectomy (P>0.05). At 24 weeks of age, detrusor muscle strip responses to carbachol from non-soy fed ovariectomised rats were attenuated (P<0.05). At 52 weeks, bladder detrusor strip responses to carbachol were reduced in all treatment groups with the exception of the soy-fed sham operated rats.

SIGNIFICANCE

These results suggest an age-related reduction in the contractile response of the detrusor to the muscarinic receptor agonist carbachol, which may be prevented by long term dietary phytoestrogen intake.

Bladder contractility is mediated by different K+ channels in the urothelium and detrusor smooth muscle

The roles played by K(+) channels in the urothelium (UE) and detrusor smooth muscle (DSM) in regulating agonist-induced bladder contraction is not known at present. Thus, the effects in carbachol (CCh)-induced contraction in UE-intact (+UE) and UE-denuded (-UE) rat detrusor strips pretreated with K(+)-channel blockers were investigated here. The K(+)-channel blockers used were 4-aminopyridine (4-AP), glibenclamide (Glib), iberiotoxin (IbTx), charybdotoxin (ChTx), and apamin. In the absence of K(+)-channel blockers, control CCh-induced contractions were more potent in -UE than +UE strips. Treatment with IbTx and apamin resulted in more potent CCh-induced contractions in +UE strips. In -UE strips, CCh potency was increased by ChTx and Glib, but decreased by 4-AP. Different K(+) channels in the UE and DSM were thus involved in regulating bladder contractions. Contractile mediatory function of these channels, specific to the UE or DSM, may be potential drug targets in the management of bladder disorders.

The role of the urothelium and ATP in mediating detrusor smooth muscle contractility

OBJECTIVES

To examine the contractility of urothelium-intact (+UE) and urothelium-denuded (-UE) rat detrusor strips under adenosine triphosphate (ATP) treatment. Purinergic signaling exists in the bladder but both the inhibitory effect of ATP on detrusor contractions and the function of urothelial ATP are not established.

METHODS

Detrusor strips were obtained from bladders of young adult rats. Isometric tension from both transverse and longitudinal contractions was measured using a myograph. The muscarinic agonist carbachol (CCh) was used to induce contractions, which were under the influences of different concentrations of ATP.

RESULTS

In both +UE and -UE strips, 1 mM ATP suppressed CCh-induced contractions. In longitudinal contractions, ATP added to the inhibitory effect of urothelium on CCh responses. Removal of the urothelium, but with exogenous ATP added, recovered the CCh responses to the same level as in +UE strips with no added ATP. Transverse contractions were less susceptible to ATP in the presence of urothelium.

CONCLUSIONS

We showed that the urothelium and ATP suppressed CCh-induced contractions to a similar extent. The findings suggest an inhibitory role of urothelial ATP in mediating detrusor smooth muscle contractility, which may be impaired in diseased bladders.

Exercise improves bladder function in diabetic mice

AIMS

We determined the effect of exercise on bladder dysfunction and voiding frequency in db/db mice.

MATERIALS AND METHODS

Diabetic db/db female mice (BKS.Cg-Dock7m +/+ Leprdb/J strain) and their age-matched wild-type controls (WT) were equally divided into sedentary and exercise groups. Mice were exercised for 1 hr everyday for 8 weeks (speed of 5.2 m/min). We performed a voiding pattern test, cystometric analysis and reactivity of isolated bladder strips in WT and db/db mice, both sedentary and exercised.

RESULTS

Diabetes increased the frequency of voiding, bladder capacity, and residual volume. Exercise decreased voiding frequency in db/db mice; voiding frequency was 5.8 ± 0.5 (db/db exercise) versus 10.8 ± 1.1 (db/db control, P < 0.001). In cystometric analysis, the bladder capacity of db/db sedentary mice was 0.27 ± 0.05 ml and was 0.14 ± 0.02 ml in the db/db exercise group (P < 0.05), whereas the residual volume was 0.2 ± 0.03 ml in db/db sedentary mice and 0.06 ± 0.02 ml in db/db Ex mice. Isolated strips of bladder muscle from sedentary db/db mice were more responsive to carbachol than strips from db/db exercise mice. Exercise did not improve the urodynamic properties of WT mice, both sedentary and exercised.

CONCLUSIONS

Exercise improves bladder function in diabetic mice by reducing voiding frequency and improving urodynamic parameters.

β-Adrenoceptor-mediated differences in transverse and longitudinal strips from the rat detrusor

Contractions and relaxations of the urinary bladder occur in all directions to facilitate urine release and storage. Transverse and longitudinal contractility of detrusor smooth muscle have been studied before using various pharmacologic stimuli but not β agonists. Given the importance of β-adrenoceptors in mediating bladder relaxation, the effects of isoprenaline (IPNA) in transverse and longitudinal contractility were examined. Pretreatment with a low concentration of IPNA (0.1 or 1 μM) suppressed carbachol (CCh)-induced contractions, more in the transverse than longitudinal direction. Increasing the IPNA concentration to 10 or 100 μM resulted in greater inhibition of longitudinal contractions. Also in the longitudinal direction, IPNA-induced relaxation was greater than in the transverse direction. When precontracted with a submaximal concentration of CCh (1 μM), IPNA increased the phasic activity in the longitudinal direction only. In summary, β-adrenoceptor-mediated differences between transverse and longitudinal contractility were revealed. In testing the relaxant properties of selective β-agonists, the findings here should be considered such that other than the conventional longitudinal contractions, measurements are also made in other directions.

Effect of estrogen and progesterone on urodynamics in the conscious rat

OBJECTIVES

To examine the effects of estrogen and/or progesterone on the cystometric profiles obtained using continuous-filling cystometry in the conscious Sprague-Dawley rat.

METHODS

Sprague-Dawley rats underwent ovariectomy (OVX) and were compared with controls by conscious continuous-filling cystometry. The effect of estrogen (10 microg/kg/d for 14 days) and/or progesterone (10 mg/kg/d for 14 days) replacement on OVX urodynamics was examined (n = 7-8/group).

RESULTS

OVX rats demonstrated reduced micturition intervals and voided volumes compared with controls. These effects of OVX were reversed by estrogen replacement, but not by progesterone replacement. When combined with estrogen, progesterone functioned to partially antagonize the effects of estrogen in OVX rats.

CONCLUSIONS

Estrogen enhances bladder capacity in the OVX rat and therefore is a likely contributor to the larger bladder capacity in the female compared with the male rat. Consistent with its established role in reproductive physiology, progesterone antagonizes the beneficial effects of estrogen on OVX rat urodynamics.

Effects of beta3-adrenergic receptor activation on rat urinary bladder hyperactivity induced by ovariectomy

Voiding dysfunctions, including increased voiding frequency, urgency, or incontinence, are prevalent in the postmenopausal population. Beta(3)-adrenergic receptor (beta(3)AR) agonists, which relax bladder smooth muscle, are being developed to treat these conditions. We utilized the rat ovariectomy (OVX) model to investigate the effect of ovarian hormone depletion on bladder function and the potential for beta(3)AR agonists to treat bladder hyperactivity in this setting. OVX increased voiding frequency and decreased bladder capacity by approximately 25% in awake rats and induced irregular cystometrograms in urethane-anesthetized rats. Reverse transcription-polymerase chain reaction revealed three betaARs subtypes (beta(1,2,3)) in bladder tissue, and immunostaining indicated beta(3)AR localization in urothelium and detrusor. Receptor expression was not different in OVX and SHAM rats. The beta(3)AR agonist selectivity of BRL37344 [(+/-)-(R(*),R(*))-[4-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]phenoxy]acetic acid sodium hydrate], TAK-677 [(3-((2R)-(((2R)-(3-chlorophenyl)-2-hydroxyethyl)amino)propyl)-1H-indol-7-yloxy)acetic acid], and FK175 [acetic acid, 2-[[(8S)-8-[[(2R)-2-(3-chlorophenyl)-2-hydroxyethyl]amino]-6,7,8,9-tetrahydro-5H-benzocyclohepten-2-yl]oxy], ethyl ester, hydrochloride] was confirmed by examining the relative potency for elevation of cAMP in CHOK1 cells overexpressing the various rat betaARs. Intravenous injection of each of the beta(3)AR agonists (0.1-500 microg/kg) in anesthetized rats decreased voiding frequency, bladder pressure, and amplitude of bladder contractions. In bladder strips, beta(3)AR agonists (10(-12)-10(-4) M) decreased baseline tone and reduced spontaneous contractions. BRL37344 (5 mg/kg) and TAK-677 (5 mg/kg) injected intraperitoneally in awake rats decreased voiding frequency by 40 to 70%. These effects were not altered by OVX. The results indicate that OVX-induced bladder dysfunction, including decreased bladder capacity and increased voiding frequency, is not associated with changes in beta(3)AR expression or the bladder inhibitory effects of beta(3)AR agonists. This suggests that beta(3)AR agonists should prove effective for the treatment of overactive bladder symptoms in the postmenopausal population.

Urinary retention and cystitis associated with subcutaneous estradiol pellets in female nude mice

Unexpected deaths occurred in studies involving a nude mouse model of mammary cancer that required subcutaneous implantation of 0.5 mg twenty-one-day release estrogen pellets for growth of the estrogen-dependent mammary tumor xenograft BT474c. Early deaths occurred in female nude mice and were associated with urinary retention, frequently with cystitis. Drug treatment had no effect on the incidence or severity of cystitis. Histological findings did not alter significantly over various time points following pellet implantation. Changes were not seen in males or in females receiving lower doses of estradiol even when the duration of administration was prolonged, suggesting that a threshold level was required for the onset of urinary retention. Because of the influence of estrogen on micturition, immunohistochemistry for estrogen receptor alpha (ERalpha) in the urinary bladder was carried out, which did not demonstrate any differences between females implanted with 0.5 mg twenty-one-day release estrogen pellets and nonimplanted females. Although previous publications have concentrated on possible mechanisms of action, this paper describes the histopathological changes seen in the urinary bladder of female nude mice resulting from exposure to high levels of estradiol.

The effect of testosterone alone and testosterone + estradiol therapy on bladder functions and smooth muscle/collagen content in surgically menopause induced rats

OBJECTIVES

The aim of the study was to investigate the effect of testosterone alone and testosterone+estradiol therapy on bladder functions and smooth muscle/collagen content in surgically menopause induced rat model.

METHODS

The study included 34 female Sprague-Dawley rats, and the rats were divided into four groups. After bilateral oophorectomy, during a 60 days period, six rats received IM saline injection for one time, as a control group, and nine rats received testosterone undecanoate 100mg/kg IM for one time, and nine rats received testosterone undecanoate 100mg/kg IM for one time + daily 0.50mg nasal spray of 17beta estradiol. Ten rats were taken as sham group. Urodynamic studies were performed in all groups before and after the study. The rats were sacrificed after 60 days, and cystometric findings and smooth muscle/collagen ratio of the bladders were compared between the groups.

RESULTS

Increase in maximal bladder capacity and compliance were significantly higher in the testosterone treatment group and testosterone + estradiol treatment group than in the control group (p = 0.01 and p = 0.002, respectively for bladder capacity; p = 0.04 and p = 0.005, respectively for bladder compliance). Smooth muscle/collagen ratio of the bladders was significantly higher in the testosterone and testosterone + estradiol treatment groups than in the control group (p = 0.04 and p = 0.008, respectively).

CONCLUSIONS

This study shows that bladder functions may deteriorate in postmenopausal period. In addition to estrogen replacement therapy, testosterone has a significant role to increase bladder smooth muscle, leading to improvement in bladder functions in postmenopausal women with urogenital system dysfunction.

The effect of chronic inflammatory condition of the bladder and estrogen replacement therapy on bladder functions and histology in surgically menopause and chronic cystitis induced rats

AIMS

We investigated the effect of chronic inflammatory condition of the bladder and estrogen replacement therapy on bladder function and histological changes in surgically menopause and chronic cystitis induced rats.

METHODS

The study included 36 female Sprague-Dawley rats, divided into five groups. After bilateral ovariectomy, chronic cystitis was induced by intravesical instillation of HCl, and then group 1 (n = 8) received nasal estrogen, and group 2 (n = 8) received oral estrogen replacement therapy. Group 3 (n = 7) underwent ovariectomy and chronic cystitis, but no replacement therapy. Group 4 (n = 7) had only ovariectomy. Group 5 (n = 6) was taken as sham group. The rats were sacrificed after 60 days, and cystometric study and histological findings were compared among the groups.

RESULTS

The mean maximal bladder capacity and compliance revealed significant decreases in group 3 and 4 compared with group 5, and significant increases in group 1 and 2 compared with group 3. Histological findings showed significant increases in the mast cells and leukocyte infiltration of group 3 and 4 compared with group 5, and significant decreases in the mast cells and leukocyte infiltration of group 1 and 2 compared with group 3.

CONCLUSIONS

This experimental menopause and chronic cystitis model showed that bladder function and histology might deteriorate much more with chronic cystitis in postmenopausal period. This is the first study in the literature to report that chronic inflammatory bladder occurring after menopause can be improved by estrogen replacement therapy.

A dose-dependent dual effect of oestrogen on voiding in the male mouse?

OBJECTIVES

To explore the effect of different degrees of oestrogenization on male voiding, by treating adult castrated and 5alpha-dihydrotestosterone (DHT)-maintained male mice with different doses of oestrogens, as exposure of male mice to excessive amounts of oestrogens can cause bladder outlet obstruction (BOO); in addition, male mice lacking oestrogen receptor (ER)alpha (ERKO) or ERbeta (BERKO) were studied to assess the importance of ER subtypes.

MATERIALS AND METHODS

Castrated, DHT-maintained adult mice were treated with 17beta-oestradiol (E(2); 50 and 250 microg/kg) or oestrone (E(1); 5, 50 and 500 microg/kg) daily for 10 days. Control mice were treated only with the vehicle. BERKO and ERKO mice, and their wild-type littermates used as their controls, remained untreated. Under anaesthesia, the bladder and distal urethra were exposed to record simultaneously the bladder pressure and urinary flow rate from the distal urethra.

RESULTS

E(2)-treated mice showed obstructive voiding, seen as increased bladder pressure, decreased average flow rate and prolonged micturition time. This was also evident when a high dose (500 microg/kg) of E(1) was used. After treatment with a dose of 50 microg/kg, the urodynamic variables were similar to those in the control mice. Surprisingly, after treatment with a low dose (5 microg/kg) all urodynamic variables improved. There was a minor increase in the bladder pressure in BERKO mice; ERKO mice had a significantly lower urinary flow rate.

CONCLUSIONS

High doses of oestrogens caused BOO in castrated, DHT-maintained male mice. A small dose of E(1) had a positive effect on voiding, suggesting that oestrogens are needed for normal male voiding. Reduced urinary flow rates in ERKO mice suggest that oestrogen effects on voiding are mediated at least partly via ERalpha.

Pharmacology of the lower urinary tract: basis for current and future treatments of urinary incontinence

The lower urinary tract constitutes a functional unit controlled by a complex interplay between the central and peripheral nervous systems and local regulatory factors. In the adult, micturition is controlled by a spinobulbospinal reflex, which is under suprapontine control. Several central nervous system transmitters can modulate voiding, as well as, potentially, drugs affecting voiding; for example, noradrenaline, GABA, or dopamine receptors and mechanisms may be therapeutically useful. Peripherally, lower urinary tract function is dependent on the concerted action of the smooth and striated muscles of the urinary bladder, urethra, and periurethral region. Various neurotransmitters, including acetylcholine, noradrenaline, adenosine triphosphate, nitric oxide, and neuropeptides, have been implicated in this neural regulation. Muscarinic receptors mediate normal bladder contraction as well as at least the main part of contraction in the overactive bladder. Disorders of micturition can roughly be classified as disturbances of storage or disturbances of emptying. Failure to store urine may lead to various forms of incontinence, the main forms of which are urge and stress incontinence. The etiology and pathophysiology of these disorders remain incompletely known, which is reflected in the fact that current drug treatment includes a relatively small number of more or less well-documented alternatives. Antimuscarinics are the main-stay of pharmacological treatment of the overactive bladder syndrome, which is characterized by urgency, frequency, and urge incontinence. Accepted drug treatments of stress incontinence are currently scarce, but new alternatives are emerging. New targets for control of micturition are being defined, but further research is needed to advance the pharmacological treatment of micturition disorders.

Influence of estradiol pretreatment on antimuscarinic action of oxybutynin in rat detrusor muscle

OBJECTIVES

To investigate the antimuscarinic effect of oxybutynin in the rat detrusor muscle after estrogen pretreatment because, to our knowledge, no study has been done on the interaction of estrogen with antimuscarinic drugs. Estrogen has been shown to affect muscarinic receptors in the detrusor muscle of animals. In addition, oxybutynin has been shown to block muscarinic receptors in the bladder.

METHODS

Estradiol benzoate (150 microg/kg) or saline was given subcutaneously to virgin female Wistar albino rats (n = 6, each group) for 10 consecutive days. On the 11th day, isolated detrusor muscle strips were taken, and acetylcholine (ACh)-induced contractions were evaluated in the absence or presence of oxybutynin (10 and 100 nM).

RESULTS

ACh induced concentration-dependent contractions in the detrusor muscle. In the estradiol-pretreated group, the maximum of the ACh-induced contractions was diminished compared with that in the control group (P < 0.05). Oxybutynin (10 and 100 nM) inhibited ACh-induced contractions competitively (pK(B) 8.85). In the estradiol-pretreated group, the concentration-response curve to ACh was shifted further to the right in the presence of oxybutynin (100 nM).

CONCLUSIONS

We have demonstrated for the first time that oxybutynin further inhibits ACh-induced and muscarinic receptor-mediated contractions in rat detrusor muscle after pretreatment with estrogen.

Estrogen receptor subtypes and afferent signaling in the bladder

PURPOSE

The influence of estrogen on bladder function has been the subject of several experimental and clinical studies. In addition to the well-known estrogen receptor (ER)alpha, recently the ER subtype ERbeta was discovered. We investigated potential changes in bladder function in mice lacking either 1 or both receptor subtypes compared with WT mice.

MATERIALS AND METHODS

Female mice lacking genes for ERalpha (ERKO), ERbeta (BERKO) or both and their WT littermates were used for the study. Continuous cystometry in awake animals was performed before and after intravesical administration of capsaicin. In addition, in vitro responses to electrical field stimulation before and after incubation with scopolamine and alpha,beta-methylene adenosine triphosphate, and to carbachol were investigated.

RESULTS

Control cystometry revealed no significant difference in urodynamic parameters among all strains. After capsaicin instillation the micturition interval and volume decreased, and micturition pressure increased in WT, ERbeta and 2 gene mice, while no changes were seen in ERKO mice. In vitro contractility was similar in all groups. Incubation with scopolamine and alpha,beta-methylene adenosine triphosphate led to significant decreases in the response to electrical field stimulation. There was no difference in the response to carbachol among the groups.

CONCLUSIONS

The lack of ERalpha and/or ERbeta had little effect on in vitro contractility or on continuous cystometry in awake animals. The lack of response to capsaicin instillation in ERKO suggests that ER subtypes are important for vanilloid receptor function and mechano-afferent signaling.