The purpose of this study was to determine the role of cyclooxygenase-2 (COX-2) and its metabolites in lower urinary tract function after induction of acute (4 h), intermediate (48 h), or chronic (10 day) cyclophosphamide (CYP)-induced cystitis. Bladders were harvested from euthanized female rats for analyses. Conscious cystometry was used to assess the effects of a COX-2-specific inhibitor, 5,5-dimethyl-3-(3-fluorophenyl)-4-(4-methylsulfonyl)phenyl2(5H)-furanone (DFU, 5 mg/kg sc), a disubstituted furanone, in CYP-induced cystitis. COX-2 mRNA was increased in inflamed bladders after acute (12-fold) and chronic (9-fold) treatment. COX-2 protein expression in inflamed bladders paralleled COX-2 mRNA expression. Prostaglandin D2-methoxime expression in the bladder was significantly (P < or = 0.01) increased in acute (3-fold) and chronic (5.5-fold) cystitis. Prostaglandin E2 was significantly (P < or = 0.01) increased (2-fold) in the bladder with intermediate (1.7-fold) and chronic (2.6-fold) cystitis. COX-2-immunoreactive cell profiles were distributed throughout the inflamed bladder and coexpressed histamine immunoreactivity. Conscious cystometry in rats treated with CYP + DFU showed increased micturition intervals 4 and 48 h after CYP treatment and decreased intravesical pressures during filling and micturition compared with rats treated with CYP + vehicle. These studies suggest an involvement of urinary bladder COX-2 and its metabolites in altered micturition reflexes with CYP-induced cystitis.

These studies demonstrate that the use of the NGF sequestering protein REN1820 in rats with CYP induced cystitis decreases bladder overactivity. This is characterized by 1) a decrease in the number and amplitude of nonvoiding contractions and 2) decreased voiding frequency. Rats treated with REN1820 showed greater mobility and normal resting postures, which may reflect improved overall health or well-being. REN1820 may prove to be a novel therapeutic in individuals with the chronic inflammatory bladder syndrome interstitial cystitis.

The role of JAK-STAT signaling in urinary bladder inflammation and referred somatic sensitivity has not been addressed. The contribution of JAK-STAT signaling pathways in CYP-induced bladder hyperreflexia and referred somatic hypersensitivity was determined in CYPtreated rats using a JAK2 inhibitor, AG490. Acute (4 h; 150 mg/kg ip), intermediate (48 h; 150 mg/kg ip), or chronic (75 mg/kg ip, once every 3 days for 10 days) cystitis was induced in adult, female Wistar rats with CYP treatment. Phosphorylation status of STAT-3 was increased in urinary bladder after CYP-induced cystitis (4 h, 48 h, chronic). Blockade of JAK2 with AG490 (5-15 mg/kg ip or intravesical) significantly (P Յ 0.05) reduced bladder hyperreflexia and hind paw sensitivity in CYP-treated rats. These studies demonstrate a potential role for JAK-STAT signaling pathways in bladder hyperreflexia and referred pain induced by CYP-induced bladder inflammation. somatic sensitivity; bladder hyperreflexia; cystometry; AG490 CLINICAL SYMPTOMS OF INTERSTITIAL CYSTITIS (IC)/painful bladder syndrome (PBS) include bladder and/or pelvic pain, urinary frequency, and urgency (17, 44). The pathophysiologic mechanisms of IC/PBS are not fully understood but current research hypotheses include bladder urothelial dysfunction, mast cell activation and recruitment, and neurogenic inflammation (41). Potential mediators of urinary bladder inflammation are numerous and include cytokines (19,36,40), chemokines (55), neuropeptides (5, 49), neuroactive compounds (4), and growth factors (51, 54,56). Of these mediators, a number of cytokines have been implicated in animal models of urinary bladder inflammation and in IC/PBS human studies. For example, interleukin-6 (IL-6) expression is markedly increased in urine of IC/PBS patients (19,36). Bladder inflammation in rats and mice induced by cyclophosphamide (CYP) increased transcript and protein expression in urinary bladder of several cytokines, including 40). Furthermore, the IL-6 cytokine family member leukemia inhibitory factor (LIF) is also regulated at the transcript and protein levels in the urinary bladder by CYP-induced cystitis and increased protein expression is exhibited in the urothelium, detrusor smooth muscle, and in nerve fibers of the suburothelial plexus (7) with CYP-induced cystitis.LIF and IL-6 receptor interactions, among others (3, 12, 14, 21, 30), induce transphosphorylation of the receptor-associated Janus-activated kinases (JAK), which in turn leads to phosphorylation of the downstream signal transducer and activator of transcription (STAT) family of transcription factors (JAK-STAT pathway) (18,30). The IL-6 family of cytokines also activates mitogen-activated protein kinase (MAPK) signaling pathways and associated transcription factors (21). Inhibition of JAK-STAT3 signaling pathway by AG490, a member of the tyrphostin family of tyrosine kinase inhibitors, reduces inflammatory changes in bronchial epithelial cells (26) and neuropathic pain stemming from peripheral nerve injury (14). Previous studies (11...

These studies demonstrate that 1) CYP induced cystitis up-regulates PAR2 to 4 expression in the bladder, 2) PAR2 to 4 is expressed in urothelium, detrusor muscle and bladder nerve fibers in control and CYP treated rats, and 3) bladder C-fibers and bladder afferent cells in dorsal root ganglia express PAR2 to 4. These results suggest the involvement of PARs in bladder inflammation that contributes to altered sensory processing and reflex function.