Dual involvements of cyclooxygenase and nitric oxide synthase expressions in ketamine‐induced ulcerative cystitis in rat bladder

Abstract

Aims:The aims of the present study were to investigate voiding patterns, tissue constituents and the expressions of cyclooxygenase-2 (COX-2) and nitric oxide synthase (NOS) involved in ketamine-induced ulcerative cystitis in rat urinary bladder. Methods: Thirty Sprague-Dawley rats were distributed into three groups which received saline or ketamine (25 mg/kg/day) for a period of 14 and 28 days. In each group, cystometry was performed weekly and the concentration of ketamine and its metabolites (norketamine) was assayed. Paraffin-embedded sections were stained with Masson's trichrome stain, and ketamine-induced morphological changes were examined. Western blot analyses were carried out to examine the expressions of COX-2 and different NOS isoforms in bladder tissues. Immunofluorescence study was done to evaluate the expressions of COX-2 and macrophage infiltration (stained with ED-1 macrophage cell surface antigen) within the bladder. Results: Ketamine treatment resulted in bladder hyperactivity and the non-voiding contractions were significantly increased. The urine concentrations of ketamine and norketamine were much higher in ketamine-treated group. Moreover, ulcerated urothelium and mononuclear cell infiltration were noted in ketamine-treated group. These alterations in urodynamic functions and tissue constituents were accompanied by increases in the expression of COX-2. Two NOS isoforms (iNOS and eNOS) were also overexpressed, but no significant change was observed for nNOS. COX-2 positive stained cells were significantly increased. Meanwhile, increased amounts of ED-1 positive stained macrophages were present and most of COX-2 expressed cells were co-stained with ED-1 in the early stage of ketamine treatment. Conclusions: Ketamine treatment affected bladder tissues by enhancing interstitial fibrosis and accelerating macrophages infiltration. Ketamine also initiated the up-regulations of COX-2 and iNOS and eNOS expressions. These up-regulated enzymes might play an important role in contributing to ketamine-induced alterations in micturition patterns and ulcerative cystitis.

Demonstration of the direct impact of ketamine on urothelium using a tissue engineered bladder model

“…As mentioned by some authors, 7,13,17,18 there could be immunologic and vascular factors involved in KIC that we could not demonstrate with our Impact of ketamine on urothelium model. Nonetheless, this limitation is also an advantage.…”

“…Recent studies on animal models and histologic samples of KIC patients showed important inflammatory processes and macrophage infiltration. 13,15,18 It is clear that the direct effect of ketamine is not the only mechanism involved in KIC. However, in the absence of these other phenomenon, we were able to demonstrate that the sole presence of ketamine was enough to induce apoptosis in human urothelial cells in monolayer and on 3D tissue-engineered VE.…”

Translocation of NF-κB and Expression of Cyclooxygenase-2 Are Enhanced by Ketamine-Induced Ulcerative Cystitis in Rat Bladder

“…injection 15 ), and iii) a ketamine þ Cox-2 inhibitor group [ketamine combined with COX-2 inhibitor (parecoxib sodium; Dynastat [Pfizer, New York, New York]) 10 mg/kg per day by i.p. injection 23 ]; each group was treated for 28 days.…”

“…As previously described, 15,24 the rats were placed in individual KDS-TL380 metabolic cages and the MLT0380 transducer (AD Instruments, Colorado Springs, CO). Micturition Q12 frequency and the volume of urine output were recorded for 3 days, and a mean value was determined.…”

“…13,14 We have previously shown in a rat model that ketamine treatment enhances bladder interstitial fibrosis; alternates in micturition Q7 patterns; accelerates macrophage infiltration; and initiates the upregulation of Cox-2, inducible nitric oxide synthase, and endothelial nitric oxide synthase Q8 expression. 15 Moreover, the increased expression of COX-2 in bladder stromal cells may be a potential prognostic biomarker of urothelial cancer, especially of cancer-specific death and recurrence. 16 Transcription factor NF-kB plays a crucial role in inflammatory response.…”