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.

Cyclophosphamide (CYP)-induced cystitis alters micturition function and produces reorganization of the micturition reflex. This reorganization may involve cytokine expression in the urinary bladder. These studies have determined candidate cytokines in the bladder that may contribute to the reorganization process. An RNase protection assay was used to measure changes in rat bladder cytokine mRNA [interferon-γ (IFN)-γ, interleukin-1α/β (IL-1α/β), IL-2, IL-3, IL-4, IL-5, IL-6, IL-10, and tumor necrosis factor-α/β (TNF-α/β)] after acute (4 h), intermediate (48 h), or chronic (10 day) cystitis. The correlation between bladder cytokine mRNA and protein expression was also determined by immunoassay. Although at each time point after cystitis significant changes in bladder cytokine mRNA were observed, the magnitude differed (acute > intermediate > chronic). Acute cystitis demonstrated the most robust changes ( P ≤ 0.005; IL-1β, 330-fold increase; IL-2, 20-fold increase; IL-4, 8-fold increase; IL-6, 80-fold increase) in cytokine mRNA expression and TNF-α or TNF-β mRNA were only increased (2–10-fold) after acute cystitis. More modest increases in cytokine mRNA expression were observed after 48-h or 10-day cystitis. Cytokine protein expression generally paralleled that of mRNA. Increased cytokine expression after CYP-induced cystitis, alone or in combination with other inflammatory mediators or growth factors, may contribute to altered lower urinary tract function after cystitis.

Cystitis decreases bladder NGF and BDNF expression, whereas MPG expression is increased. This change may reflect neurotrophin release at the bladder and retrograde transport to the MPG. TrkA-IR and TrkB-IR are increased in bladder postganglionic cells and bladders with cystitis. This increase may reflect a shift in Trk staining from urothelium to detrusor muscle and nerve fibers with cystitis. Neurotrophin/Trk interactions in the bladder and MPG may contribute to bladder overactivity with cystitis.

Cheppudira BP, Girard BM, Malley SE, Schutz KC, May V, Vizzard MA. Upregulation of vascular endothelial growth factor isoform VEGF-164 and receptors (VEGFR-2, Npn-1, and Npn-2) in rats with cyclophosphamide-induced cystitis.

Merrill L, Malley S, Vizzard MA. Repeated variate stress in male rats induces increased voiding frequency, somatic sensitivity, and urinary bladder nerve growth factor expression. Am J Physiol Regul Integr Comp Physiol 305: R147-R156, 2013. First published May 8, 2013 doi:10.1152/ajpregu.00089.2013.-Stress exacerbates symptoms of functional lower urinary tract disorders including interstitial cystitis (IC)/bladder pain syndrome (BPS) and overactive bladder (OAB) in humans, but mechanisms contributing to symptom worsening are unknown. These studies address stress-induced changes in the structure and function of the micturition reflex using an animal model of stress in male rats. Rats were exposed to 7 days of repeated variate stress (RVS). Target organ (urinary bladder, thymus, adrenal gland) tissues were collected and weighed following RVS. Evans blue (EB) concentration and histamine, myeloperoxidase (MPO), nerve growth factor (NGF), brain-derived neurotropic factor (BDNF), and CXCL12 protein content (ELISA) were measured in the urinary bladder, and somatic sensitivity of the hindpaw and pelvic regions was determined following RVS. Bladder function was evaluated using continuous, open outlet intravesical infusion of saline in conscious rats. Increases in body weight gain were significantly (P Յ 0.01) attenuated by day 5 of RVS, and adrenal weight was significantly (P Յ 0.05) increased. Histamine, MPO, NGF, and CXCL12 protein expression was significantly (P Յ 0.01) increased in the urinary bladder after RVS. Somatic sensitivity of the hindpaw and pelvic regions was significantly (P Յ 0.01) increased at all monofilament forces tested (0.1-4 g) after RVS. Intercontraction interval, infused volume, and void volume were significantly (P Յ 0.01) decreased after RVS. These studies demonstrate increased voiding frequency, histamine, MPO, NGF, and CXCL12 bladder content and somatic sensitivity after RVS suggesting an inflammatory component to stress-induced changes in bladder function and somatic sensitivity. micturition; stress; nerve growth factor; ELISA; somatic sensitivity STRESS CONTRIBUTES to symptom exacerbation in many disease states, including functional disorders of the urinary bladder such as overactive bladder (OAB) and interstitial cystitis (IC)/ bladder pain syndrome (BPS) (3,38,58,72). Urinary frequency is a common symptom among patients with OAB or IC/BPS, although the end result of frequent voiding may differ [reduce incontinence episodes (OAB) vs. reduce pain with bladder filling (IC/BPS)]. Patients with IC/BPS report symptom worsening during stress, as do patients with other disorders associated with IC/BPS including rheumatoid arthritis, psoriasis, and irritable bowel syndrome (47,72). Symptom worsening during stress may be due, in part, to disruption of the hypothalamic-pituitary-adrenal (HPA) axis. Cortisol, through feedback on the HPA axis, normally acts to attenuate inflammation (47); however, abnormalities in the feedback may cause dysregulation of the inflammatory response. Therefore, patients...