RESUMO
Cyclooxygenase (COX)-2 is an inducible isoform, expressed in inflamed leukocytes and cancer cells. It is known that estrogen causes prostate dysplasia, but little is known about COX-2 expression and its influence on male reproductivity. In this study, we show that COX-2 was abolished in the distal end of the vas deferens in neonatally estrogenized (diethylstilbestrol, NeoDES) Sprague-Dawley (SD) rats at age of 15 mo, but the control normal rats were found to remain constitutive expression at the same age, while the levels of COX-1 in these rats remained intact. Furthermore, BAX, an indicator of sperm quality, was observed in the endothelium of vas deferens and sperm of the aged rats. However, COX-2 was not detected in the inflamed lesions of NeoDES rat's prostate by immunohistochemistry. In addition to estrogen, hydroxymatairesinol (HMR), a phytoestrogen, was analyzed in vitro for possible regulation on COX-2. Through Western blot analysis, HMR was shown to have no inhibitory affect on COX-2 expression. These results indicated that estrogen treatment strongly influences the expression of COX-2 that is associated with fertility, but no induction of COX-2 by estrogen may not exclude COX-2's role in prostatitis, and the anti-tumor mechanism of HMR largely remains elusive.