ABSTRACT
PURPOSE: We hypothesize that bacillus Calmette-Guerin (BCG) may act through the regulation of various isoforms of nitric oxide synthase (NOS) [inducible (iNOS), endothelial (eNOS), and neuronal (nNOS)] genes and proteins expressions in rat bladder. MATERIALS AND METHODS: Adult female Sprague Dawley rats (200-250g) were injected into the urinary bladder transurethrally with BCG (22 rats) or saline (22 control rats) and after 2, 4, 6, and 12 hrs, and 1, 2, 3, 5, 7, 10 and 14 days, the bladders were harvested. Normal and BCG-treated rat bladders were analyzed for mRNA expressions for iNOS, eNOS, and nNOS by reverse transcriptase-polymerase chain reaction (RT- PCR). Protein expressions were determined by Western blotting analysis and immunohistochemistry. RESULTS: mRNA expression for iNOS was induced after 2 hrs of BCG injection in the rat bladder. Gene expression for iNOS was highest at 6 hrs and followed by decreased expression from 1 day, reaching its lowest level at 5 days. eNOS mRNA expression was detected in control bladders but its level was higher in the BCG-treated animals. nNOS mRNA expression was present in all the samples but did not change after BCG treatment. Western blotting analysis confirmed these findings. Immunohistochemical analysis demonstrated that eNOS was present mainly in endothelium, while iNOS was detected in stroma and inflammatory cells, and nNOS in epithelium and smooth muscle of rat bladder. CONCLUSIONS: The present study demonstrates that BCG treatment up-regulates gene and protein expressions of iNOS and eNOS in rat bladders, suggesting that BCG action may be mediated through NOS pathways.