Animal Model Of Cystitis Research Articles

Hidrox® and Chronic Cystitis: Biochemical Evaluation of Inflammation, Oxidative Stress, and Pain.

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic bladder condition characterized by frequent urination, inflammation, oxidative stress, and pain. The aim of the study was to evaluate the anti-inflammatory and antioxidant effects of an oral administration of Hidrox® (10 mg/kg) in the bladder and spinal cord in a rodent model of IC/BPS. The chronic animal model of cystitis was induced by repeated intraperitoneal injections of cyclophosphamide (CYP) for five consecutive days. Treatment with Hidrox® began on the third day of the CYP injection and continued until the 10th day. CYP administration caused macroscopic and histological bladder changes, inflammatory infiltrates, increased mast cell numbers, oxidative stress, decreased expression of the tight endothelial junction (e.g., zonula occludens-1 (ZO-1) and occludin), and bladder pain. Treatment with Hidrox® was able to improve CYP-induced inflammation and oxidative stress via the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) pathway. It was also able to reduce bladder pain which was aggravated by the activation of neuroinflammation in the central nervous system. In particular, Hidrox® reduced the brain-derived neurotrophic factor (BDNF), as well as the activation of astrocytes and microglia, consequently reducing mechanical allodynia. These results indicate that nutritional consumption of Hidrox® can be considered as a new therapeutic approach for human cystitis, increasing the conceivable potential of a significant improvement in the quality of life associated with a lowering of symptom intensity in patients with IC/BPS.

Increased Gene Expression of Circulating Pro‐inflammatory Cytokines in Felines with Idiopathic Cystitis

Feline idiopathic cystitis (FIC) is one of the common urinary disorders of domestic cats. Inflammation is a key characteristic in the pathogenesis of cystitis and pro-inflammatory cytokines and chemokines have been hypothesized to contribute to the progression of cystitis. Several cytokines have been reported in the urine and bladder in animal models of cystitis and in humans. Circulating levels of cytokines and chemokines are important biomarkers to assess the presence and severity of FIC and may also be useful as a response variable to assess dietary intervention. We assessed the circulating inflammatory markers in a retrospective study in cats with cystitis (n=6; 9.2-18.6 yr) from blood samples collected at necropsy, as well as in control cats (n=6; 5.9-14.6 yr). While most cats had been diagnosed with idiopathic cystitis during their life-time, two cats also were diagnosed with urinary tract infection. End-of-life pathology reports indicated inflammation and presence of inflammatory infiltrates in the bladder (lamina propria) with some cats also showing renal inflammation. RNA was extracted from blood samples, and we assessed the circulating levels of inflammatory genes using ThermoFisher Scientific Custom TaqMan array plates that were feline-specific, in the blood of cats obtained at the end-of-life. Data were analyzed using the using the ΔΔCt method using HPRT as the housekeeping gene. The levels of circulating mRNA that were increased greater than 1.5-fold in the FIC cats, when compared to controls, included interleukin-4 (>1.96-fold), interleukin-1b (>1.75), bone morphogenetic protein -2 (>1.74), interleukin-8 (CXCL8; >1.73), interleukin-16 (>1.7), and CSF-1 (>1.58). While IL-4 may have some anti-inflammatory effects, an increase in IL-4 can also lead to T-cell proliferation and increased inflammation. An increase in IL-16, a chemoattractant and activator of T-cells, as well as IL-8, indicates an important role of T-cell activation in the pathogenesis and progression of cystitis. Our results identify elevated levels of several pro-inflammatory molecules that may be potential targets for alleviating chronic inflammation associated with cystitis. Nutritional intervention to reduce the levels of selected inflammatory cytokines may be useful in the management of cystitis

THE ANTI‐INFLAMMATORY EFFECTS OF ADELMIDROL + SODIUM HYALURONATE (VESSILEN®) IN PRECLINICAL AND CLINICAL STUDIES

Interstitial cystitis/painful bladder syndrome (IC/PBS) is a chronic bladder condition characterized by frequent urination, bladder inflammation and pain. It is a particular challenging disease and a clear unmet medical need in terms of identifying new therapeutic strategies. Adelmidrol, the diethanolamide derivative of azelaic acid, represents an effective treatment for human inflammatory disorders. The aim of study was first, to evaluate the anti‐inflammatory effects of intravesical Vessilen® administration (a new formulation of 2% adelmidrol + 0.1% sodium hyaluronate) in acute and chronic animal models of cystitis induced by a single or repetitive intraperitoneal injection of cyclophosphamide (CYP) and then, in patients with IC/PBS treated once weekly by endo‐bladder instillation of Vessilen® for 8 weeks.CYP instillation caused macroscopic and histological bladder alterations, inflammatory infiltrate, increased mast cell number and bladder pain that were reduced by Vessilen® treatment. In addition, an increased expression of nitrotyrosine, a marker of oxidative stress and a decreased expression of endothelial tight junction zonula occludens‐1 were found in CYP‐injected animals. Vessilen® diminished nitrotyrosine and increased zonula occludens‐1 formation. To characterize the inflammatory state and possible reactive oxygen species‐induced pathways involved during chronic cystitis, we also analyzed the nuclear factor‐κB pathway and expression of inducible nitric oxide synthase, interleukin‐1β and monocyte chemoattractant protein‐1. Vessilen® inhibited nuclear factor‐κB pathway and inflammatory mediator levels. Moreover, an increase in nerve growth factor was also found in chronic CYP‐induced cystitis triggering inflammatory response and mechanical hyperalgesia. In that regard, Vessilen® treatment reduced mechanical allodynia and nerve growth factor levels. Interestingly, a reduction in symptom intensity and a significant improvement in the assessment of quality of life were also evident in IC/PBS patients treated with Vessilen®.Thus, in conclusion, we demonstrate that Vessilen® treatment could be a new therapeutic approach in the treatment of human cystitis.Support or Funding Informationno fundingThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Manipulating the extracellular matrix: an animal model of the bladder pain syndrome.

Bladder pain syndrome (BPS) is associated with breakdown of the protective uroepithelial barrier of the urinary bladder allowing urinary constituents access to bladder sensory neurons. Although there are several animal models of cystitis, none specifically relates to BPS. Here, we aimed to create such a model using enzymatic digestion of the barrier proteoglycans (PGs) in the rat. Twenty female Wistar rats were anaesthetized and transurethrally catheterized. Ten animals were treated with 0.25IU of intravesical chondroitinase ABC and heparanase III to digest chondroitin sulphate and heparin sulphate PGs, respectively. Ten animals received saline. Following PG deglycosylation, bladders showed irregular loss of the apical uroplakin and a significant increase in neutrophils, not evident in the control group. Spinal cord sections were also collected for c-fos analysis. A large and significant increase in fos immunoreactivity in the L6/S1 segments in the treatment vs control bladders was observed. Cystometry was performed on 5 treatment and 5 control animals. Analysis revealed a significant increase in micturition reflex excitability postdeglycosylation. On a further group of 10 animals, von Frey mechanical withdrawal thresholds were tested on abdominal skin before and after PG digestions. There was a significant decrease in abdominal mechanical withdrawal threshold postdeglycosylation compared with controls. The results of this animal study suggest that many of the clinical features of BPS are seen after PG digestion from the bladder lumen. This model can be used to further understand mechanisms of pain in patients with BPS and to test new therapeutic strategies.

Estimating postvoid residual volume without measuring residual bladder volume during serial cystometrograms.

The postvoid residual volume (PVR) is a common urodynamic parameter used to quantify the severity of lower urinary tract dysfunction. However, the serial cystometrograms that are typically used to assess bladder function in animal models make measuring PVR very difficult. Current approaches are to either remove PVR after each void to measure it, which is disruptive to the bladder, or to neglect the unknown contribution to PVR from ureter flow, which results in inaccurate estimates. We propose a procedure to estimate PVR during a serial cystometrogram that requires only a single measurement, rather than measuring after each void. Moreover, this measurement can occur at the end of the experiment such that it does not affect the bladder during data collection. We mathematically express PVR for all voids during a serial cystometrogram using a linear recurrence equation and use this equation to build an estimation procedure for PVR. Using in vivo measurements in urethane anesthetized rats and computer simulations we show that the estimation procedure is at least as accurate in determining PVR as the traditional method of measuring PVR after each void. Furthermore, we demonstrate the adverse effects of repeated PVR measurements in a common animal model of cystitis. Using the proposed procedure can increase the efficiency and accuracy of determining PVR for a serial cystometrogram and is less disruptive to the system under study. This, in turn, allows the calculation of other urodynamic parameters that are critical for research studies, including voiding efficiency and bladder capacity.

Differences in neurotransmitter systems of ventrolateral periaqueductal gray between the micturition reflex and nociceptive regulation: An in vivo microdialysis study.

To elucidate the possible involvement of glutamate and serotonin (5-hydroxytryptamine) neurons in the ventrolateral midbrain periaqueductal gray during noxious stimulation. The study was carried out by evoking a noxious stimulation by acetic acid in an animal model of cystitis. Changes in glutamate and 5-hydroxytryptamine in the periaqueductal gray during the micturition reflex and acetic acid-induced cystitis were determined using in vivo microdialysis combined with cystometry in rats. Extracellular glutamate levels slightly, but significantly, increased during the micturition reflex induced by saline infusion into the bladder. Intravesical infusion of acetic acid facilitated the micturition reflex characterized by increases in voiding pressure and decreases in the intercontraction interval. Glutamate levels were markedly increased by acetic acid, and this enhancement was sustained for at least 3 h. 5-Hydroxytryptamine levels, which were not altered during the micturition reflex, were increased after intravesical infusion of acetic acid. The results suggest that periaqueductal gray glutamate and 5-hydroxytryptamine neurons differentially participate in the modulation of both nociception and the micturition reflex. Furthermore, periaqueductal gray 5-hydroxytryptamine levels appear to reflect the nociceptive stimuli.

Artemin Immunotherapy Is Effective in Preventing and Reversing Cystitis-Induced Bladder Hyperalgesia via TRPA1 Regulation

Injury- or disease-induced artemin (ARTN) signaling can sensitize primary afferents and contribute to persistent pain. We demonstrate that administration of an ARTN neutralizing antibody, anti-artemin (α-ARTN), can block the development of, and reverse already established, bladder hyperalgesia associated with cyclophosphamide-induced cystitis in mice. We further demonstrate that α-ARTN therapy blocks upregulation of TRPA1, an ion channel contributing to persistent bladder pain during cyclophosphamide-induced cystitis, and decreases phospho-ERK1/2 immunoreactivity in regions of the spinal cord receiving bladder afferent input. Thus, α-ARTN is a promising novel therapeutic approach for treatment of bladder hyperalgesia that may be associated with interstitial cystitis/painful bladder syndrome, as well as cystitis associated with antitumor or immunosuppressive cyclophosphamide therapy. Perspectiveα-ARTN therapy effectively prevented and reversed ongoing bladder hyperalgesia in an animal model of cystitis, indicating its potential as an efficacious treatment strategy for ongoing bladder pain associated with interstitial cystitis/painful bladder syndrome.

Detrusor myocyte autophagy protects the bladder function via inhibiting the inflammation in cyclophosphamide-induced cystitis in rats.

Autophagy, a highly conserved homeostatic cellular process that removes and recycles damaged proteins and organelles in response to cellular stress, is believed to play a crucial role in the immune response and inflammation. The role of autophagy in bladder cystitis, however, has not well been clarified. Here we investigate the role of detrusor myocytes autophagy (DMA) in cyclophosphamide-induced cystitis animal model. 164 female Sprague-Dawley rats were randomized into three experimental groups and compared to three control groups, respectively. The expressions of microtubule-associated protein 1 light chain 3 (LC3), p-p70s6k (the phosphorylated form of ribosomal protein S6), SOD2 (superoxide dismutase 2) in the bladder muscular layer were measured using western blot. The co-location of LC3, alpha-smooth muscle actin (α-SMA), and autophagic vacuoles were investigated with double-labeled immunofluorescence and transmission electron microscopy (TEM). The expression of lL-1β, IL-6, IL-8, malondialdehyde (MDA), and glutathione (GSH) in the detrusor layer were analyzed using ELISA. The bladder inflammation and the number of mast cells in the muscular layer were analyzed by histology. The bladder function was evaluated using cystometry. In cyclophosphamide-induced cystitis, autophagy was detected in detrusor myocytes by increased LC3, p-p70s6k expression, and autophagosomes. However, the presence of enhanced inflammation and oxidative stress in the cyclophosphamide-treated group suggest autophagy of detrusor myocytes may not be sufficiently activated. Inflammation and oxidative stress were significantly decreased and the bladder histology and micturition function were significantly improved with rapamycin (RAPA, autophagy agonist) pre-treatment. In contrast, inflammation and oxidative stress were dramatically increased and the bladder histology and function were negatively affected with chloroquine (CQ, autophagy blocker) pre-treated. These findings preferentially provide evidence of the association between DMA and cyclophosphamide-induced cystitis in rats. The autophagy agonist RAPA significantly decreased the inflammation and protected the bladder function, which might be considered as a potential treatment for interstitial cystitis.

Effects of Vitamin D Analog on Bladder Function and Sensory Signaling in Animal Models of Cystitis

To measure the effects of nonhypercalcemic vitamin D receptor agonist elocalcitol on bladder function in rats with cyclophosphamide-induced cystitis and on bladder function and sensory nerve activity in a mouse with acetic acid-evoked bladder irritation. Female Wistar rats and male Balb/C mice were gavaged once daily with elocalcitol diluted in miglyol 812 (treatment group) or miglyol alone (control group). On experimental day 12, polyethylene tubing was implanted into the urinary bladder in all the animals. In the mice, a bipolar electrode was positioned under a single postganglionic bladder nerve. At 48 hours after surgery, bladder function was measured in awake, freely moving rats during bladder filling with 0.9% NaCl and both bladder function and sensory nerve activity was measured in awake, restrained mice during continuous intravesical infusion of 0.9% NaCl followed by 0.25% acetic acid. In rats, the treatment group showed a significant increase in bladder capacity and decrease in number of nonvoiding bladder contractions. In mice, the filling pressure during saline infusion was similar in both groups; however, during acetic acid infusion, the average filling pressure was significantly increased (47%) in the control group but not in the elocalcitol treatment group. The firing rate at filling pressure for the treatment group was 3.6-fold and 2.7-fold lower than that in the control group during the saline and acetic acid infusion, respectively. Oral treatment with elocalcitol suppressed signs of detrusor overactivity in both animal models and exerted strong suppressive effect on urinary bladder sensory signaling during filling in mice.

Effects of Intravesical Dexpanthenol Use on Lipid Peroxidation and Bladder Histology in a Chemical Cystitis Animal Model

To demonstrate the effects of intravesical dexpanthenol use on bladder histology and lipid peroxidation in a chemical cystitis animal model. Thirty-five New Zealand rabbits were divided into 3 groups. Cystitis was conducted with transurethral intravesical hydrochloric acid instillation on the subjects in groups I and II. Then, Group I subjects were transurethrally administered intravesical dexpanthenol therapy twice a week, Group II subjects were given only intravesical isotonic NaCl instillation, and Group III subjects were administered intravesical isotonic NaCl instillation without conducting chemical cystitis to create the same stress. Treatment schemes of all groups were arranged in the same manner. After 6-week therapy, the rabbits were sacrificed and histopathologic investigations were carried out to demonstrate changes in the urinary bladder. Serum and tissue malondialdehyde (MDA) values were examined to investigate the effect of dexpanthenol on lipid peroxidation. We observed that the basal membrane and mucosal integrity were maintained, inflammatory cells were suppressed, and MDA levels decreased in group I, which received dexpanthenol therapy. However, it was also observed that mucosal integrity was spoiled, numerous inflammatory cells were accumulated, and MDA levels were significantly increased in group II, which was administered isotonic NaCl. In light of our findings, intravesical dexpanthenol therapy could be a new therapeutic approach in the treatment of interstitial cystitis because of its low cost and acceptable side effects.

Urothelial TRPV1: TRPV1-Reporter Mice, a Way to Clarify the Debate?

Urothelial TRPV1: TRPV1-Reporter Mice, a Way to Clarify the Debate?

Intracellular Lifestyles and Immune Evasion Strategies of UropathogenicEscherichia coli

Paradigms in the pathogenesis of urinary tract infections have shifted dramatically as a result of recent scientific revelations. Beyond extracellular colonization of the bladder luminal surface, as traditional clinical thinking would hold, uropathogenic bacteria direct a complex, intracellular cascade that shelters bacteria from host defenses and leads to persistent bacterial residence within the epithelium. After epithelial invasion, many organisms are promptly expelled by bladder epithelial cells; a minority establish a niche in the cytoplasm that results in the development of biofilm-like intracellular bacterial communities and serves as the primary location for bacterial expansion. Exfoliation of the superficial epithelial layer acts to reduce the bacterial load but facilitates chronic residence of small nests of bacteria that later reemerge to cause some episodes of recurrent cystitis, a familiar clinical scenario in otherwise healthy women. Advances in both in vitro and animal models of cystitis promise to provide insights into the bacterial and host transcriptional and biochemical pathways that define these pathogenic stages.

Combination of protamine sulfate and potassium chloride in establishing the interstitial cystitis animal model

Objective To investigate the reliability and feasibility of the combination of protamine sul-fate and potassium chloride in establishing interstitial cystitis animal model. Methods Thirty female SD rats (250-300 g) were randomly divided into experimental group and control group. The experimental group was randomly divided into 3 groups, 1-month group, 2-month group and 3-month group; the control group was also divided into 3 groups, with 5 for each group. The rat bladders in experimental group were filled with 10 mg/ml protamine sulfate and 500 mmol/L potassium chloride, while the rat bladders in the control group were filled with sodium chloride solution. At the end of the experiment, the bladders of all the SD rats were dyed with the HE staining to observe the level of inflammation and count the number of mono-nuclear inflammatory cells of the la-mina propria, or with special staining to observe and count the mast cells. Results The experimental groups showed significant prevalence of inflammation and there were a large number of mononuclear inflammatory cells (36.80±6.28, 79.20±4.40, 89.60±5.50 cells / field in different experimental groups, respectively) and a small number of mast cells (2.80±0.37, 2.60±0.24, 3.40±0.24 cells / field, correspondingly). The counts of mononuclear inflammatory cells underneath the lamina propria among the three experimental groups were statistically significant (P=0.000), while the 2-month group and 3-month group was not significant (P=0.202). The differences of mast cells underneath the lamina propria among the three experimental groups were not significant (P=0.178). The control groups had no significant bladder inflammation performance, there was no mast cells, only rare mononuclear inflammatory cells (7.00±0.71, 8.00±0.71, 8.20±1.24 cells/field, respectively). The difference among the three control groups was not significant (P=0.625). The differences between the experimental group and control group were significant(P=0.008, P=0.000). Conclusions The application of the combina-tion of protamine sulfate and potassium chloride to establish interstitial cystitis animal model is reliable and feasible. Researchers can choose the right time of irrigation based on the intent of the experiment. Key words: Protamine sulfate; Potassium chloride; Interstitial cystitis; Animal , experiment

ALTERED INDUCIBLE NITRIC OXIDE SYNTHASE EXPRESSION AND NITRIC OXIDE PRODUCTION IN THE BLADDER OF CATS WITH FELINE INTERSTITIAL CYSTITIS

Alterations in nitric oxide (NO) levels have been demonstrated in some humans with interstitial cystitis (IC) as well as in chemically induced animal models of cystitis. Thus, in the current study we investigated whether inducible NO synthase (iNOS) mediated NO production is altered in the bladder of cats with a naturally occurring model of IC termed feline IC (FIC). We examined iNOS expression using Western immunoblotting and baseline NO production using an NO microsensor from smooth muscle and mucosal bladder strips in 9 healthy cats and 6 diagnosed with FIC. There was a significant increase in baseline NO production in cats with FIC compared with that in healthy cats in smooth muscle and mucosal strips. This production was not ablated in the absence of extracellular Ca (100 microM egtazic acid) or following incubation with the calmodulin antagonist trifluoroperazine (20 microM), indicating iNOS mediated Ca independent NO production. Release was significantly decreased following incubation with the NOS antagonist L-NAME (N-nitro-L-arginine methyl ester) (100 microM). Furthermore, immunoblotting revealed a trend toward increased iNOS expression in smooth muscle and mucosal strips from FIC cats but not from healthy cats. In light of previous findings that the barrier property of the urothelial surface is disrupted in FIC and iNOS mediated increase in NO alters barrier function in other types of epithelium our findings suggest that iNOS dependent NO production may have a role in epithelial barrier dysfunction in FIC.

Gene Expression Profiling of Mouse Bladder Inflammatory Responses to LPS, Substance P, and Antigen-Stimulation

Inflammatory bladder disorders such as interstitial cystitis (IC) deserve attention since a major problem of the disease is diagnosis. IC affects millions of women and is characterized by severe pain, increased frequency of micturition, and chronic inflammation. Characterizing the molecular fingerprint (gene profile) of IC will help elucidate the mechanisms involved and suggest further approaches for therapeutic intervention. Therefore, in the present study we used established animal models of cystitis to determine the time course of bladder inflammatory responses to antigen, Escherichia coli lipopolysaccharide (LPS), and substance P (SP) by morphological analysis and cDNA microarrays. The specific aim of the present study was to compare bladder inflammatory responses to antigen, LPS, and SP by morphological analysis and cDNA microarray profiling to determine whether bladder responses to inflammation elicit a specific universal gene expression response regardless of the stimulating agent. During acute bladder inflammation, there was a predominant infiltrate of polymorphonuclear neutrophils into the bladder. Time-course studies identified early, intermediate, and late genes that were commonly up-regulated by all three stimuli. These genes included: phosphodiesterase 1C, cAMP-dependent protein kinase, iNOS, beta-NGF, proenkephalin B and orphanin, corticotrophin-releasing factor (CRF) R, estrogen R, PAI2, and protease inhibitor 17, NFkB p105, c-fos, fos-B, basic transcription factors, and cytoskeleton and motility proteins. Another cluster indicated genes that were commonly down-regulated by all three stimuli and included HSF2, NF-kappa B p65, ICE, IGF-II and FGF-7, MMP2, MMP14, and presenilin 2. Furthermore, we determined gene profiles that identify the transition between acute and chronic inflammation. During chronic inflammation, the urinary bladder presented a predominance of monocyte/macrophage infiltrate and a concomitant increase in the expression of the following genes: 5-HT 1c, 5-HTR7, beta 2 adrenergic receptor, c-Fgr, collagen 10 alpha 1, mast cell factor, melanocyte-specific gene 2, neural cell adhesion molecule 2, potassium inwardly-rectifying channel, prostaglandin F receptor, and RXR-beta cis-11-retinoic acid receptor. We conclude that microarray analysis of genes expressed in the bladder during experimental inflammation may be predictive of outcome. Further characterization of the inflammation-induced gene expression profiles obtained here may identify novel biomarkers and shed light into the etiology of cystitis.

Increased expression of growth-associated protein (GAP-43) in lower urinary tract pathways following cyclophosphamide (CYP)-induced cystitis

Alterations in the expression of growth-associated protein 43 (GAP-43) were examined in lower urinary tract micturition reflex pathways in a chronic model of cyclophosphamide (CYP)-induced cystitis. In control animals, expression of GAP-43 was present in specific regions of the gray matter in the rostral lumbar and caudal lumbosacral spinal cord, including: (1) the dorsal commissure; (2) the dorsal horn and (3) the regions of the intermediolateral cell column (L 1–L 2) and the sacral parasympathetic nucleus (L 6–S 1) and (4) in the lateral collateral pathway of Lissauer in L 6–S 1 spinal segments. Densitometry analysis has demonstrated significant increases ( p≤0.001; 1.5–4.0-fold increase) in GAP-43-immunoreactivity (IR) in these regions of the rostral lumbar (L 1–L 2) and caudal lumbosacral (L 6–S 1) spinal cord following CYP-induced urinary bladder inflammation. Changes in GAP-43-IR were restricted to those segmental levels examined (L 1–L 2 and L 6–S 1) that are involved in lower urinary tract reflexes. Changes in GAP-43-IR were not observed at the L 5 segmental level. In contrast to significant increases in GAP-43-IR in specific regions of the rostral lumbar and caudal lumbosacral spinal cord, no changes in GAP-43-IR were observed in the L 1, L 2 or L 6, S 1 dorsal root ganglia (DRG). In control animals, virtually all retrogradely labeled (Fast Blue) bladder afferent cells in the L 1, L 2 and L 6, S 1 DRG expressed GAP-43-IR. This percentage (∼100%) of bladder afferent cells expressing GAP-43-IR was unchanged following CYP-induced urinary bladder inflammation. Alterations in GAP-43-IR following chronic cystitis may suggest a reorganization of bladder afferent projections and spinal elements involved in bladder reflexes consistent with alterations in bladder function observed in animal models of cystitis.

The modulatory effects of Bradykinin B 1 and B 2 receptor antagonists upon viscero-visceral hyper-reflexia in a rat model of visceral hyperalgesia

This study assessed the relative involvement of the two bradykinin (Bk) receptors (B 1 and B 2) in the viscero-visceral hyper-reflexia (VVH) and plasma extravasation observed in an animal model of cystitis. The effects of the competitive receptor antagonists des-Arg 9[Leu 8]-Bk (B 1) and HOE 140 (B 2) were tested both in prophylactic (pre-inflammation administration) and therapeutic (post-inflammation administration) scenarios. Compared with control animals, des-Arg 9[Leu 8]-Bk had no effect on the hyper-reflexic response of the bladder to inflammation unless it was administered 5 h after inflammation. However, HOE 140 was able to attenuate the inflammation-induced viscero-visceral hyper-reflexia (VVH) at doses of 1 mg/kg, 2 mg/kg and 7.5 mg/kg. This effect was apparent whether the drug was administered before, or after inflammation. In contrast, neither compound was effective in attenuating the intravesical plasma extravasation induced by turpentine. The data therefore suggest that the VVH and tissue inflammation responses are mediated via different mechanisms. In addition, the turpentine-induced VVH appears to be mediated, at least partially, by the B 2 receptor in the early phase, with the B 1 receptor only becoming important later.

Effects of Sensitization on the Permeability of Urothelium in Guinea Pig Urinary Bladder

Permeability of the guinea pig urinary bladder was investigated in a model of experimental cystitis induced by intravesical antigen challenge following sensitization. Guinea pigs were sensitized by intraperitoneal injections of ovalbumin (10 mg./kg.) given on days 1, 3, and 5. The studies described were done four weeks after the last injection. Controls (injected with saline) were used at the same time as sensitized animals. Each group (control and sensitized), was divided into two subgroups; guinea pigs challenged with intravesical ovalbumin (10 mg./ml., one ml.) and those receiving one ml. saline intravesically. Immediately following the antigen (or saline) challenge, one ml. of 14C-urea urea was placed into the bladder for two hours. We examined the peripheral blood concentrations of 14C-urea at periods of time up to 120 minutes. There was a progressive increase in the blood level of 14C-urea with time only in the sensitized group challenged with antigen (ovalbumin). There was no 14C-urea present in the blood of the sensitized group without antigen challenge, or in either unsensitized group. We also measured isotope concentration in the bladders and found a significantly higher concentration of isotope in the bladders from ovalbumin-treated sensitized guinea pigs. We believe that this animal model of cystitis is an improvement over previous models because of its physiological relevance. In this model, cystitis is produced without mechanical or chemical damage to the bladder mucosa. A discussion of the model in relation to interstitial cystitis is presented.