Time-course of alterations of bladder function following acetone-induced cystitis

Animal Modelling of Interstitial Cystitis/Bladder Pain Syndrome

The etiology of interstitial cystitis/bladder pain syndrome (IC/BPS) remains elusive and may involve multiple causes. To better understand its pathophysiology, many efforts have been made to create IC/BPS models. Most existing models of IC/BPS strive to recreate bladder-related features by applying noxious intravesical or systemic stimuli to healthy animals. These models are useful to help understand various mechanisms; however, they are limited to demonstrating how the bladder and nervous system respond to noxious stimuli, and are not representative of the complex interactions and pathophysiology of IC/BPS. To study the various factors that may be relevant for IC/BPS, at least 3 different types of animal models are commonly used: (1) bladder-centric models, (2) models with complex mechanisms, and (3) psychological and physical stressors/natural disease models. It is obvious that all aspects of the human disease cannot be mimicked by a single model. It may be the case that several models, each contributing to a piece of the puzzle, are required to recreate a reasonable picture of the pathophysiology and time course of the disease(s) diagnosed as IC/BPS, and thus to identify reasonable targets for treatment.

Comparison of 5 Different Rat Models to Establish a Standard Animal Model for Research Into Interstitial Cystitis

Purpose

We evaluated 5 different rat models using different agents in order to establish a standard animal model for interstitial cystitis (IC) in terms of the functional and pathologic characteristics of the bladder.

Methods

Five IC models were generated in 8-week-old female Sprague-Dawley rats via transurethral instillation of 0.1M hydrogen chloride (HCl) or 3% acetic acid (AA), intraperitoneal injection of cyclophosphamide (CYP) or lipopolysaccharide (LPS), or subcutaneous injection of uroplakin II (UPK2). After generating the IC models, conscious cystometry was performed on days 3, 7, and 14. All rats were euthanized on day 14 and their bladders were obtained for histological and pro-inflammatory-related gene expression analysis.

Results

In the cystometric analysis, all experimental groups showed significantly decreased intercontraction intervals compared with the control group on day 3, but only the LPS and UPK groups maintained significantly shorter intercontraction intervals than the control group on day 14. The histological analysis revealed that areas with severe urothelial erosion (HCl, AA, and UPK) and hyperplasia (CYP and LPS), particularly in the UPK-treated bladders, showed a markedly increased infiltration of toluidine blue-stained mast cells and increased tissue fibrosis. In addition, significantly elevated expression of interleukin-1b, interleukin-6, myeloperoxidase, monocyte chemotactic protein 1, and Toll-like receptors 2 and 4 was observed in the UPK group compared to the other groups.

Conclusions

Among the 5 different agents, the injection of UPK generated the most effective IC animal model, showing consequent urothelial barrier loss, inflammatory reaction, tissue fibrosis stimulation, and persistent hyperactive bladder.

Uroplakin peptide-specific autoimmunity initiates interstitial cystitis/painful bladder syndrome in mice

The pathophysiology of interstitial cystitis/painful bladder syndrome (IC/PBS) is enigmatic. Autoimmunity and impaired urothelium might lead the underlying pathology. A major shortcoming in IC/PBS research has been the lack of an appropriate animal model. In this study, we show that the bladder specific uroplakin 3A-derived immunogenic peptide UPK3A 65–84, which contains the binding motif for IA^d MHC class II molecules expressed in BALB/c mice, is capable of inducing experimental autoimmune cystitis in female mice of that strain. A highly antigen-specific recall proliferative response of lymph node cells to UPK3A 65–84 was observed, characterized by selectively activated CD4+ T cells with a proinflammatory Th1-like phenotype, including enhanced production of interferon γ and interleukin-2. T cell infiltration of the bladder and bladder-specific increased gene expression of inflammatory cytokines were observed. Either active immunization with UPK3A 65–84 or adoptive transfer of peptide-activated CD4+ T cells induced all of the predominant IC/PBS phenotypic characteristics, including increased micturition frequency, decreased urine output per micturition, and increased pelvic pain responses to stimulation with von Frey filaments. Our study demonstrates the creation of a more specific experimental autoimmune cystitis model that is the first inducible model for IC/PBS that manifests all of the major symptoms of this debilitating condition.

Chemical cystitis due to crystal violet dye: a case report

Introduction

Crystal violet was commonly used for the treatment of oral and vaginal candidiasis or for sterilization during operations up to the 1960s. Because crystal violet is potentially toxic to mucosal membranes, it has been replaced with other disinfectants, and crystal violet is rarely used. We report a case of chemical cystitis due to intravesical instillation of crystal violet dye.

Case presentation

Crystal violet dye was instilled into the bladder of a 47-year-old Japanese woman to confirm the presence of a vesicovaginal fistula. Our patient developed symptoms of gross hematuria, frequent urination and lower abdominal pain. Computed tomography showed thickening of her whole bladder wall with spotted high-density lesions. Cystoscopy demonstrated desquamated epithelial cells and a hemorrhagic bladder wall. We treated our patient conservatively with nonsteroidal anti-inflammatory drugs and glucocorticoids. During follow-up, magnetic resonance images showed that the detrusor muscle of her bladder was normal. Our patient’s symptoms gradually improved and she completely recovered within six months.

Conclusion

Considering the severe side effect of crystal violet, it would be better not to use this dye to examine conditions such as a vesicovaginal fistula. Magnetic resonance imaging may help to evaluate the level of damage in the bladder wall of patients with chemical cystitis.

Comparison of voiding function and nociceptive behavior in two rat models of cystitis induced by cyclophosphamide or acetone

AIMS

Nociceptive behavior and its relationship with bladder dysfunction were investigated in two cystitis models, which were induced by intraperitoneal (i.p.) injection of cyclophosphamide (CYP) or intravesical instillation of acetone, using freely moving, non-catheterized conscious rats.

METHODS

Female Sprague-Dawley rats were used. Cystitis was induced by i.p. injection of CYP (100 and 200 mg/kg) or intravesical instillation of acetone (10%, 30%, and 50%) via a polyethylene catheter temporarily inserted into the bladder through the urethra. Then the incidence of nociceptive behavior (immobility with decreased breathing rates) was scored. Voided urine was collected simultaneously and continuously to measure bladder capacity. The plasma extravasation in the bladder was quantified by an Evans blue (EB) dye leakage technique.

RESULTS

CYP (100 mg/kg, i.p.) induced nociceptive behavior without affecting bladder capacity or EB concentration in the bladder. A higher dose of CYP (200 mg/kg, i.p.) decreased bladder capacity and increased EB levels as well as nociceptive behavior. In contrast, intravesical instillation of acetone (30%) decreased bladder capacity and increased EB levels, but evoked nociceptive behavior less frequently compared with CYP-treated animals. In capsaicin-pretreated rats, nociceptive behavior induced by CYP or acetone was reduced; however, the overall effects of CYP or acetone on bladder capacity and bladder EB levels were unaffected.

CONCLUSIONS

These results suggest that there is a difference in the induction process of nociceptive behavior and small bladder capacity after two different types of bladder irritation, and that C-fiber sensitization is more directly involved in pain sensation than reduced bladder capacity.

MK-801 inhibits the micturition reflex in chronic bladder irritation caused by crystalluria in the rat

Urodynamic and pharmacological studies were performed to investigate the effect of crystalluria on the micturition reflex and the involvement of glutamatergic transmission. The rats, which were given LP-805 (100 mg/kg/day) orally for 12 days, voided crystalluria. The pH of these crystalluria (LP-805 urine) was the same as normal urine. The amount of crystals was 70-100/division magnified 400 x. The end of the crystals was sharp. Intravesical administration of LP-805 urine induced hyperreflexia of the micturition reflex in normal rats. When the infusion solution was changed to LP-805 urine from saline, the latency was reduced to 57.6+/-2.1% of control in single cystometrogram (CMG) or was reduced to 51.4+/-0.9% of control in continuous CMG. The voiding volume was reduced to 52.1+/-3.6% of control in single CMG or was reduced to 62.5+/-0.8% of control in continuous CMG. These parameters were recovered after LP-805 urine was removed. Intravesical administration of acetic acid did not induce hyperreflexia of the micturition reflex in LP-805-treated rats. These data suggest that the chronic irritation by aculeate crystals might induce hyperreflexia of the micturition reflex, which increase afferent neuronal activity. Intravenous administration of MK-801 (0.001 to 1 mg/kg) inhibited the micturition reflex in a dose-dependent manner. The ID50 in LP-805-treated rats (0.03 mg/kg i.v.) was lower than that in normal rats (0.56 mg/kg i.v.). After chronic irritation of the bladder epithelium, MK-801 sensitivity was enhanced for the micturition reflex. These data suggested that crystalluria elicit hyperreflexia in the micturition reflex that mediated with NMDA glutamatergic receptors.

In vivo models of interstitial cystitis

PURPOSE

We systematically identified and evaluated various animal models that have been studied to help identify the underlying mechanisms of and possible treatment options for interstitial cystitis.

MATERIALS AND METHODS

Models of interstitial cystitis published between 1983 and 2001 were obtained by searching MEDLINE and other Internet databases using cystitis and model as the primary key words. Models with characteristics of interstitial cystitis similar to those defined by National Institutes of Arthritis, Diabetes, Digestive and Kidney Diseases criteria were reviewed. Some articles describing animal models with similar pathological conditions in other organs were also included to enlarge the base of potentially relevant material.

RESULTS

We identified and evaluated some 16 animal models of interstitial cystitis, which we categorized as bladder inflammation induced by intravesical administration of an irritant or immune stimulant, systemic and environmentally induced inflammation, and a naturally occurring model of interstitial cystitis that occurs in cats. Some abnormalities identified in humans and cats with interstitial cystitis can be reproduced in healthy animals using luminal, systemic or environmental stimuli. At the level of the bladder the source of stimulation cannot be discriminated. Variability in the extent of bladder distention complicated the interpretation of some studies. In addition, the noxious stimuli used can affect many epithelial surfaces as well as the urothelium, suggesting they are nonspecific responses to injury rather than specific to interstitial cystitis.

CONCLUSIONS

No model in bladder injury in healthy animals currently reproduces as many features of interstitial cystitis as the naturally occurring disease in cats. While induced models of relative injury may help to provide insight into the bladder response to injury, feline interstitial cystitis follows a similar chronic waxing and waning time course as does interstitial cystitis in humans, which may be more suitable for studying the effects of stressors on the severity of clinical signs as well as newly proposed therapies.

Urodynamics in acetone-induced cystitis of anesthetized rats

We examined the bladder function of cystitis models induced by intravesical acetone instillation in urethane-anesthetized rats. Acetone (0.35 ml) at 10, 30, or 50% concentration or deionized water (sham-treatment) was instilled into the bladder via the cannula which was inserted into the lumen. Acetone was withdrawn 90 sec after instillation and the bladder lumen was washed with saline after 15 min. One hour later, the cystometrogram induced by transvesical infusion of saline (3.3 ml/hr) was measured. During cystometrography of normal (non-treated) or sham-treated group, the time required to cause micturition, reflecting bladder capacity, was 9.6 +/- 0.9 (n = 7) or 10.0 +/- 0.8 min (n = 6), respectively. In the 10% acetone-treated group, the bladder capacity was similar to that in the normal or sham group. In the 30% acetone group, the time to micturition was 4.4 +/- 0.4 min (n = 7), indicating decreased bladder capacity, although the micturition pressure and the threshold pressure were not significantly different from those in the normal or sham group. However, in the 50% acetone group, the micturition reflex disappeared. In isolated rat bladder strips, contractile responses to carbachol or electrical field stimulation in the sham and 30% acetone group were similar. While, both responses in isolated strips from the 50% acetone group were reduced. The degree of damage from degeneration and desquamation of epithelium and hemorrhage in the bladder tissue from the 30% acetone group was less prominent than in the 50% acetone group. Additionally, some tissue from the 50% acetone group showed degeneration of muscle layer. The effects of three drugs were investigated in the 30% acetone group which showed increased urinary frequency. Baclofen (100 microg/kg, i.v.) and morphine (100 microg/kg, i.v.) increased significantly the bladder capacity and the threshold pressure. Atropine (10 microg/kg, i.v.) decreased the micturition pressure. These results suggest that cystitis models induced by intravesical instillation of 30% acetone may be valuable for evaluating drugs for the treatment of urinary frequency.

Comparative response of rabbit bladder smooth muscle and mucosa to anoxia

Recent studies indicate that the mucosa of the urinary bladder plays a major role in the maintenance of normal bladder function. Previous studies have demonstrated that rabbit bladder mucosa has higher rates of basal glycolysis and oxidative phosphorylation than that of bladder smooth muscle. The current study compares the response of rabbit bladder mucosa and smooth muscle compartments to anoxia. The results demonstrate that the rate of high energy phosphate degradation of the mucosa is significantly greater than the rate of high energy phosphate degradation of the smooth muscle. The implication is that the mucosa would be significantly more sensitive to ischemia than the smooth muscle of the bladder. This hypothesis may be extremely relevant to conditions such as interstitial cystitis and recurrent urinary bladder infections, in which ischemia has been implicated in their etiology.

Irritable bladder syndrome in an animal model: a continuous monitoring study

Irritable bladder syndrome (IBS) was induced in four female African green monkeys (Cercopithecus aethiops) by the use of intravesical instillation of acetone. The animals were housed in a modified metabolic cage for continuous micturition monitoring, and two uroflowmeters connected to a remote PC monitored the frequency, voided volumes, and peak flows. Before and after, urea absorption studies and urodynamics were obtained for each animal. Urea absorption increased significantly after acetone instillation and returned to baseline after 4 weeks (26 to 66 to 32%). Intravesical acetone instillation produced marked effects on bladder physiology in the first week. Bladder compliance dropped from a baseline of 10.47 to 0.58 ml/cm H2O. The voiding pattern changed from a normal pattern with a mean voided volume of 17.58 ml into marked increase in frequency and dribbling pattern with few voids (mean = 5.03 ml). Systematic behavioral observations were carried out for 4 hours per day utilizing an observation program on a laptop computer. Activity patterns, attention, sterotypic behaviors, and self-directed activities were recorded for each monkey. The animals demonstrated decreased frequency of activity and increased frequency in self-directed activities (groom, scratch), behaviors consistent with an animal experiencing pain or discomfort. The findings suggested that IBS induction in monkeys is feasible and produces a clinical picture similar to interstitial cystitis in humans. It offers a suitable animal model to enhance the understanding of voiding dysfunction with its neural pathways and to test the different therapeutic modalities to control IBS.

3H-thymidine uptake by the rat urinary bladder after induction of diabetes mellitus

Streptozotocin-induced diabetes mellitus causes diuresis, increases in bladder mass and changes in micturition. Temporal changes in micturition and bladder mass after induction of diabetes with streptozotocin were monitored and correlated with DNA synthesis and 3H-thymidine incorporation. There were increases in water consumption, urine excretion, urinary frequency, and mean and maximal micturition volume within 1 day after induction of diabetes. These parameters reached maximal values within 6 to 11 days and were maintained at 30 and 60 days. Bladder mass was significantly elevated by 7 days and did not increase further with increasing duration of diabetes. DNA concentration was decreased in bladders from 4, 7 and 14 day diabetics. 3H-thymidine incorporation into DNA increased within 2 days after induction of diabetes, reached maximal values at 4 to 7 days and declined to control values by 14 days. Autoradiography showed intense labelling of the urothelium one day after induction of diabetes, with labelling remaining high up to day 7. Connective tissue and smooth muscle labelling were slower to develop. Labelling of smooth muscle was transient, appearing only on days 4 and 7. The time course of the events was consistent with the hypothesis that bladder distension or increasing micturition volume stimulates thymidine incorporation into DNA, resulting in an increase in bladder mass.

Metabolic studies on rabbit bladder smooth muscle and mucosa

Recent studies indicate that the mucosa of the urinary bladder may play a major role in the maintenance of normal bladder function. The mucosal surface of the urinary bladder serves as a protective layer against the irritative solutes found in the urine. The integrity of this barrier can be broken by overdistension, anoxia, detergents, alcohols, bacterial infection and by contact with agents to which the mucosa has been sensitized. In view that both anoxia and ischemia can mediate a breakdown in the role of the mucosal layer as a permeability barrier, it is reasonable to assume that this function is dependent on cellular metabolism. As an initial investigation we have compared a variety of biochemical and metabolic parameters between the mucosal layer (consisting of the lamina propria, urothelium, and any connective tissue and vascular tissue within this layer); and the muscularis layer. The results of these studies demonstrated that the rate of glucose metabolism to lactic acid (LA) of the mucosa was more than three-fold greater than that of the smooth muscle. The rate of CO2 production of the mucosa was 60% greater than that of the unstimulated smooth muscle. The maximal activity of the mitochondrial enzyme citrate synthase was significantly greater in the mucosa than in the smooth muscle, however, the activity of malate dehydrogenase was similar for both tissues. The maximal activity of the cytosolic enzyme creatine kinase was more than two-fold greater in the bladder smooth muscle than in the mucosa; although the affinities of the creatine kinase isoforms of the mucosa were significantly greater than those of the muscle.(ABSTRACT TRUNCATED AT 250 WORDS)

The effect of furosemide-induced diuresis on rabbit micturition and bladder contractile function

The morphology and contractile function of the urinary bladder can be significantly altered in response to specific forms of physiological and pathophysiological stress placed upon it. For example, partial outlet obstruction results in a marked increase in bladder mass (weight) with associated alterations in the contractile response to specific forms of stimulation. Diabetes and its associated diuresis also induce significant alterations in bladder weight and contractile function. The current study was designed to determine if the increase in bladder weight induced by diuresis is associated with contractile alterations similar to those observed following partial outlet obstruction. Diuresis was induced by continual slow-infusion of furosemide using osmotic pumps. The results can be summarized as follows: 1) After two weeks of furosemide treatment the bladder mass was significantly greater than in the controls. 2) Furosemide-treated rabbits consumed and excreted three times more fluid than did the controls. 3) In vivo cystometric capacity and bladder compliance of the furosemide-treated rabbits were significantly increased. 4) Diuresis induced a significant increase in the contractile response of isolated bladder body strips to field stimulation, ATP, bethanechol, and KCl. 5) Furosemide treatment had no effects on the contractile responses of bladder base strips to any form of stimulation. Diuresis resulted in a significant increase in bladder weight and an associated increase in the contractile state of the bladder body, presumably through an increase in smooth muscle.

Effects of sensitization on female guinea pig urinary bladder function: in vivo and in vitro studies

Although bladder inflammation is known clinically to produce a variety of symptoms including urgency, frequency, and pain, there are only a few experimental studies that directly relate bladder inflammation with urodynamic and functional alterations. We have used the sensitized guinea pig model to study the effects of inflammation on micturition parameters, cystometry, and in vitro bladder contractility. This model depends on the allergic response of the bladder mucosa to ovalbumin, an otherwise non-irritative agent, as an antigen. In vivo exposure of the bladder to ovalbumin via urethral catheterization induced a prompt and marked increase in the number of micturitions in antigen-sensitized guinea pigs. Ovalbumin had no effects on the micturition parameters in the control group. Using in vivo cystometry, intravesical exposure to ovalbumin induced a significant decrease in both the pressure at which micturition was induced, and the volume at which micturition was induced. Ovalbumin had no effect on cystometric parameters of the control animals. In vitro exposure of whole-bladder preparations to ovalbumin induced a significant contractile response only in the bladders isolated from the sensitized guinea pigs. The responses of the isolated bladders to field stimulation and bethanechol were identical for bladders from both sensitized and control animals. In conclusion, exposure of the bladder to ovalbumin in the sensitized animal induced an increase in the frequency of micturitions and a decrease in the pressure and volume at which micturition was induced. Thus, intravesical exposure of the bladder mucosa to a substance that the bladder has been sensitized to can induce alterations in micturition that are consistent with the clinical symptoms of "urgency and frequency".