Bladder Hypersensitivity In Rats Research Articles

TRPV4 activation prevents lipopolysaccharide-induced painful bladder hypersensitivity in rats by regulating immune pathways.

Chronic inflammation in the urinary bladder is a potential risk factor for bladder dysfunction, including interstitial cystitis/bladder pain syndrome (IC/BPS). Although several studies have reported that activation of transient receptor potential vanilloid 4 (TRPV4) contributes to bladder pain and overactive bladder with a cardinal symptom of acute or chronic cystitis, others have reported its involvement in the protective response mediated by lipopolysaccharides (LPS) to secrete anti-inflammatory/pro-resolution cytokines. Therefore, we investigated the potential benefit of an intravesical TRPV4 agonist for painful bladder hypersensitivity in a rat model of LPS-induced cystitis and determined whether its effects modulate the LPS signal for inflammatory reaction, cytokine release, and macrophage phenotype change. Previously, we showed that repeated intravesical instillations of LPS induce long-lasting bladder inflammation, pain, and overactivity in rats. In the present study, concurrent instillation of the selective TRPV4 agonist GSK1016790A (GSK) with LPS into the rat bladder improved LPS-induced bladder inflammation and reduced the number of mast cells. Furthermore, co-instillation of GSK prevented an increase in bladder pain-related behavior and voiding frequency caused by LPS. Cytokine profiling showed that LPS-stimulated inflammatory events, such as the production and secretion of pro-inflammatory cytokines (CXCL1, CXCL5, CXCL9, CXCL10, CCL3, CCL5, CCL20, and CX3CL1), are suppressed by GSK. Furthermore, TRPV4 activation switched LPS-stimulated pro-inflammatory M1-type macrophages to anti-inflammatory M2-type macrophages. These results suggest that TRPV4 activation in the bladder negatively regulates the pro-inflammatory response induced by LPS and prevents bladder hypersensitivity. These TRPV4 functions may be promising therapeutic targets for refractory IC/BPS.

TRPV4 activation prevents lipopolysaccharide-induced painful bladder hypersensitivity in rats.

TRPV4 activation prevents lipopolysaccharide-induced painful bladder hypersensitivity in rats.

Gabapentin reduces painful bladder hypersensitivity in rats with lipopolysaccharide-induced chronic cystitis.

Although interstitial cystitis/bladder pain syndrome (IC/BPS) is a chronic condition causing bladder pain and urinary symptoms, effective treatments have not been established. The aim of this study was to adapt a chronic cystitis model in rats using lipopolysaccharide (LPS), which reflects IC/BPS pathology, and characterize the model's histological and behavioral effects. Furthermore, we investigated the effect of an α2δ subunit ligand, gabapentin (GBP), on bladder hypersensitivity of rats with chronic cystitis. Cystitis models were created by repeated intravesical injections of LPS. In the histological examination, the LPS‐injected group had greater inflammatory response, fibrosis, and abnormally thick re‐epithelialization. In the LPS‐injected group, LPS prompted hyperalgesia in both the lower abdomen and hind paw regions after day 1 of the first injection compared with the saline‐injected controls, without any recovery for 21 days at least. During cystometry, the LPS‐injected group showed bladder hyperactivity at all times. Systemic administration of GBP reduced cystitis‐related pain due to chronic inflammation and reduced the increased frequency of voiding in the LPS‐injected group. These results suggest that repeated intravesical injections of LPS induce long‐lasting bladder inflammation, pain, and overactivity in rats, while GBP is effective in the management of those symptoms in this chronic cystitis model. The current study identifies a relatively simple method to develop an animal model for chronic cystitis and provides evidence that GBP may be an effective treatment option for patients with IC/BPS.

Benzodiazepines Suppress Neuromodulatory Effects of Pudendal Nerve Stimulation on Rat Bladder Nociception.

Neuromodulation, as a therapeutic modality for pain treatment, is an alternative to opioid therapies and therefore receiving increased interest and use. Neuromodulation at a peripheral nerve target, in the form of bilateral electrical pudendal nerve stimulation (bPNS), has been shown to reduce bladder hypersensitivity in rats and anecdotally reduces pain in humans with pelvic pain of urological origin. Recent studies have identified a role for spinal γ-aminobutyric acid (GABA) receptors in this effect. Concomitant medication use, such as benzodiazepines, could alter responses to neuromodulation, and so before the development of a clinical trial to confirm translation of this potential therapy, the potential interactions between acute and chronic use of benzodiazepines and bPNS were examined in a preclinical model. Bladder hypersensitivity was produced by neonatal bladder inflammation in rat pups coupled with a second inflammatory insult as an adult. Diazepam (1-5 mg/kg intraperitoneal [i.p.]) or vehicle was administered acutely (with or without bPNS) and chronically (5 mg/kg subcutaneous [s.c.] daily for 2 weeks before the final experiment). bPNS was delivered as bilateral biphasic electrical stimulation of the mixed motor/sensory component of the pudendal nerves. Visceromotor responses (VMRs; abdominal muscle contractile responses to urinary bladder distension [UBD]) were used as nociceptive end points. Due to the profound effects of diazepam, the effect of midazolam (0.5-1.0 mg/kg i.p.) on VMRs and bPNS effects was also studied. Diazepam and midazolam both produced a dose-dependent, flumazenil-reversible inhibition of VMRs to UBD. bPNS resulted in statistically significant inhibition of VMRs to UBD in hypersensitive rats that had received vehicle injections. Select doses of diazepam and midazolam suppressed the inhibitory effect of bPNS on VMRs. This study suggests that inhibitory effects of bPNS on bladder pain could be suppressed in subjects receiving benzodiazepine therapy, suggesting that potential clinical testing of pudendal nerve stimulation for the treatment of painful bladder syndromes may be confounded by the use of benzodiazepines. Clinical assessment of other forms of neuromodulation should also be screened for impacts of benzodiazepines.

The effect of herpes simplex virus vector-mediated gene therapy of protein phosphatase 1α on bladder overactivity and nociception.

We studied the effect of herpes simplex virus (HSV) vectors-based gene transfer of protein phosphatase 1α (PP1α) on bladder hypersensitivity in rats. Using adult female Sprague-Dawley rats, non-replicating HSV vectors carrying PP1α or green fluorescent protein (GFP) were injected into the bladder wall. At one week after vector inoculation, cystometry and Western blot assay were performed, whereas the other experiments were performed at 2 weeks after vector inoculation. GFP-expressing cells were identified in the bladder as well as in L6/S1 dorsal root ganglia at 14 days. In cystometry, intercontraction intervals (ICI) after resiniferatoxin (RTx; TRPV1 agonist) irrigation was significantly reduced in the PP1α group in comparison with the GFP group. Moreover, RTx-induced freezing behavior events were observed significantly more frequently in the PP1α group than the GFP group. The number of c-Fos positive cells in the L6 spinal dorsal horn was significantly less in the PP1α group than in the GFP group. Western blot assay revealed lower levels of phosphorylated inositol 1, 4, 5-triphosphate receptor (p-IP3 R), and phosphorylated TRPV1 in the PP1α compared with the GFP group. HSV vectors-mediated PP1α gene therapy may be an alternative treatment modality for cystitis-related hypersensitive bladder condition at least in part via modulation of the IP3 R signaling pathway.

Spinal mechanisms of pudendal nerve stimulation-induced inhibition of bladder hypersensitivity in rats

Bilateral electrical pudendal nerve stimulation (bPNS) reduces bladder hypersensitivity in rat models of bladder pain and anecdotally reduces pain in humans with pelvic pain of urologic origin. The spinal neurochemical mechanisms of this antinociception are unknown. In the present study, bladder hypersensitivity was produced by neonatal bladder inflammation in rat pups coupled with a second inflammatory insult as an adult. Visceromotor responses (VMRs; abdominal muscle contractions) to urinary bladder distension (UBD) were used as a nociceptive endpoint under urethane-isoflurane anesthesia. bPNS consisted of bilateral biphasic electrical stimulation of the mixed motor/sensory component of the pudendal nerves. Following determination of the inhibitory effect of bPNS on VMRs, pharmacological antagonists were administered via an intrathecal catheter onto the lumbosacral spinal cord and bPNS effects on VMRs redetermined. bPNS resulted in statistically significant inhibition of VMRs to UBD in hypersensitive rats that was statistically reduced by the intrathecal administration of methysergide, WAY100636, CGP35348 and strychnine but was unaffected by naloxone, bicuculline, phentolamine, ondansetron and normal saline. This study suggests that inhibitory effects of bPNS may include serotonergic, GABA-B-ergic and glycinergic mechanisms suggesting the potential for interaction of the neuromodulatory effect with concommitant drug therapies.

This Month in Investigative Urology

No AccessJournal of UrologyThis Month in Investigative Urology1 Jun 2016This Month in Investigative Urology Karl-Erik Andersson Karl-Erik AnderssonKarl-Erik Andersson More articles by this author View All Author Informationhttps://doi.org/10.1016/j.juro.2016.03.042AboutFull TextPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail "This Month in Investigative Urology." The Journal of Urology, 195(6), pp. 1637–1638 References 1 : Integrative pathway analysis of metabolic signature in bladder cancer: a linkage to The Cancer Genome Atlas project and prediction of survival. J Urol2016; 195: 1911. Link, Google Scholar 2 : Sac-1004, a pseudo-sugar derivative of cholesterol, restores erectile function through reconstruction of nonleaky and functional cavernous angiogenesis in the streptozotocin induced diabetic mouse. J Urol2016; 195: 1936. Link, Google Scholar 3 : Liposome based intravesical therapy targeting nerve growth factor ameliorates bladder hypersensitivity in rats with experimental colitis. J Urol2016; 195: 1920. Link, Google Scholar © 2016 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 195Issue 6June 2016Page: 1637-1638 Advertisement Copyright & Permissions© 2016 by American Urological Association Education and Research, Inc.MetricsAuthor Information Karl-Erik Andersson More articles by this author Expand All Advertisement PDF downloadLoading ...

Liposome Based Intravesical Therapy Targeting Nerve Growth Factor Ameliorates Bladder Hypersensitivity in Rats with Experimental Colitis

Pelvic organ cross sensitization is considered to contribute to overlapping symptoms in chronic pelvic pain syndrome. Nerve growth factor over expression in the bladder is reportedly involved in the symptom development of bladder pain syndrome/interstitial cystitis. We examined whether a reduction of over expressed nerve growth factor in the bladder by intravesical treatment with liposome and oligonucleotide conjugates would ameliorate bladder hypersensitivity in a rat colitis model. Adult female rats were divided into 1) a control group, 2) a colitis-oligonucleotide group with intracolonic TNBS (2,4,6-trinitrobenzene sulfonic acid) enema and intravesical liposome-oligonucleotide treatments, 2) a colitis-saline group with intracolonic TNBS and intravesical saline treatments, 4) a sham oligonucleotide group with intravesical liposome-oligonucleotide treatment without colitis and 5) a sham-saline group with intravesical saline treatment without colitis. Liposomes conjugated with nerve growth factor antisense oligonucleotide or saline solution were instilled in the bladder and 24 hours later colitis was induced by TNBS enema. Effects of nerve growth factor antisense treatment were evaluated by pain behavior, cystometry, molecular analyses and immunohistochemistry 10 days after TNBS treatment. In colitis-oligonucleotide rats nerve growth factor antisense treatment ameliorated pain behavior and decreased a reduction in the intercontraction interval in response to acetic acid stimulation as well as nerve growth factor expression in the bladder mucosa. All were enhanced in colitis-saline rats compared to sham rats. Nerve growth factor over expression in the bladder mucosa and bladder hypersensitivity induced after colitis were decreased by intravesical application of liposome-oligonucleotide targeting nerve growth factor. This suggests that local antinerve growth factor therapy could be effective treatment of bladder symptoms in chronic pelvic pain syndrome.

Effects of Nitric Oxide on the Primary Bladder Afferent Activities of the Rat With and Without Intravesical Acrolein Treatment

BackgroundIt has been suggested that nitric oxide (NO) affects the afferent pathways innervating the bladder. In addition, acrolein, a metabolite of cyclophosphamide, causes bladder hypersensitivity in rats. ObjectiveWe investigated the direct effects of an NO substrate (L-arginine) and an NO synthase inhibitor (Nω-nitro-L-arginine methyl ester hydrochloride [L-NAME]) on single fiber activities of the primary bladder afferent nerves with or without acrolein application. Design, setting, and participantsFemale Sprague-Dawley rats were used. Under urethane anesthesia, a single nerve fiber primarily originating from the bladder was identified by electrical stimulation of the left pelvic nerve and by bladder distention, and it was divided by conduction velocity as Aδ fiber or C fiber. MeasurementsThe afferent activity measurements with constant bladder filling were repeated three times, and the third measurement served as the baseline observation. After that, two experiments were performed. First, L-NAME (10mg/ml) was instilled intravesically. Then L-arginine (300mg/kg) was administrated intravenously to investigate the competition with L-NAME. Second, L-arginine was administrated intravenously. Then 0.003% of acrolein or saline was instilled intravesically to obtain another three cycles of instillations. Results and limitationsForty-two single afferent fibers (Aδ fibers: n=19; C fibers: n=23) were isolated in 31 rats. When the bladder was filled with L-NAME solution, afferent activities of both Aδ and C fibers increased significantly, and L-arginine administration inhibited these stimulated responses. In addition, intravenous administration of L-arginine significantly decreased the activities of both fibers during saline instillation. Intravesical acrolein instillation significantly increased the activities of both fibers, which were inhibited by pretreatment with L-arginine. ConclusionsThe results suggest that NO synthase exists in the rat urinary bladder and clearly demonstrate that L-arginine, an NO substrate, can inhibit both Aδ and C mechanosensitive afferent fibers of the bladder in the rat. In addition, L-arginine can inhibit the activated responses of both fibers to intravesical acrolein.

Intravesical Liposome Versus Oral Pentosan Polysulfate for Interstitial Cystitis/Painful Bladder Syndrome

We evaluated the safety and efficacy of intravesical liposomes, a mucosal protective agent, compared to oral pentosan polysulfate sodium for interstitial cystitis/painful bladder syndrome. We performed a prospective longitudinal study of the effect of 2 independent treatments (intravesical liposomes and oral pentosan polysulfate sodium) in patients with interstitial cystitis/painful bladder syndrome. Ten possible responses (or measures) to treatment were monitored at 3 time points, including baseline, and weeks 4 and 8. A total of 24 patients with interstitial cystitis/painful bladder syndrome were evaluated in a 1:1 ratio to intravesical liposomes (80 mg/40 cc distilled water) once weekly or to oral pentosan polysulfate sodium (100 mg) 3 times daily for 4 weeks each. No patient had urinary incontinence, retention or infection due to liposome instillation. There were no unanticipated adverse events and no significant worsening of symptoms during followup. Statistically significant decreases in urinary frequency and nocturia were observed in each treatment group. Statistically significant decreases in pain, urgency and the O'Leary-Sant symptom score were observed in the liposome group. Decreased urgency in the liposome group had the most profound effect of the ordinal measures. Each glycosaminoglycan directed treatment seemed beneficial. Liposome intravesical instillation is safe for interstitial cystitis/painful bladder syndrome with potential improvement after 1 course of therapy for up to 8 weeks. Intravesical liposomes achieved efficacy similar to that of oral pentosan polysulfate sodium. Further large-scale placebo controlled studies are needed. Intravesical liposomes appear to be a promising new treatment for interstitial cystitis/painful bladder syndrome.