['To determine whether castration combined with pelvic congestion could cause chronic prostatitis, and to examine the effect of eviprostat in this rat model.', 'Male rats were divided into three groups, which were the sham, castration combined with pelvic congestion and castration combined with pelvic congestion plus eviprostat groups. Rats in the castration combined with pelvic congestion and castration combined with pelvic congestion plus eviprostat groups were anesthetized with isoflurane, after which ligation of the bilateral common iliac veins and castration were carried out. The sham and castration combined with pelvic congestion groups were fed a standard diet, whereas the castration combined with pelvic congestion plus eviprostat group was fed the same diet containing 0.1% eviprostat. After 4 weeks, continuous cystometry was carried out under urethane anesthesia. Then the bladder and the prostate gland were subjected to histological examination.', 'There was no significant difference of the interval between bladder contractions in the sham and castration combined with pelvic congestion plus eviprostat groups, but the interval in the castration combined with pelvic congestion group was significantly shorter than the other groups. There was no difference in the maximum bladder contraction pressure among the three groups. Pathological inflammatory changes of the bladder wall were slightly more severe in the castration combined with pelvic congestion and castration combined with pelvic congestion plus eviprostat groups than in the sham group, whereas bladder vascularity was increased in the castration combined with pelvic congestion plus eviprostat group. In addition, pathological inflammatory changes and glandular atrophy of the prostate were more severe in the castration combined with pelvic congestion and castration combined with pelvic congestion plus eviprostat groups than in the sham group.'] Does pelvic venous congestion with castration cause chronic prostatitis in rats?