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

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. Neurourol. Urodynam. 32:1137–1143, 2013. © 2013 Wiley Periodicals, Inc.     

Matrix metalloproteinase (MMP)‐3 gene up‐regulation in a rat tail compression loading‐induced disc degeneration model

The rodent static compression loading‐induced disc degeneration model still has important gaps among the radiographic, magnetic resonance imaging (MRI), and histological schemes and the acute and chronic expression of catabolic genes such as matrix metalloproteinase (MMP)‐3. Our objectives were to assess the validity of a rat tail two‐disc static compression model and to elucidate a representative catabolic marker, MMP‐3 gene alterations, throughout the degenerative process. Static compression at 1.3 MPa for up to 56 days produced progressive disc height loss in radiographs, lower nucleus intensity on T2‐weighted MRIs, and histomorphological degeneration. Real‐time RT‐PCR mRNA quantification showed significant MMP‐3 up‐regulation in nucleus pulposus cells from 7 days and a significantly progressive increase as the loading duration lengthened, with high correlations to radiological degenerative scores. Immunohistochemistry demonstrated progressively increased positive staining for MMP‐3. These results validate this animal model for disc degeneration research. Progressive mRNA and protein‐distributional up‐regulations indicate the significant role of MMP‐3 and its feasibility as a disc degenerative marker. This model should prove useful for investigating the pathomechanism and for evaluating molecular therapies for degenerative disc disease. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:1026–1032, 2010