The effect of tamoxifen on bladder functions and histology, and the role of estrogen receptor β in a rat chemical cystitis model

Aims: The purpose of this study was to investigate the effect of tamoxifen citrate on bladder functions and histology, and also to investigate the role of estrogen receptor beta (ER beta) in a rat chemical cystitis model. Methods: The study included 37 female Sprague-Dawley rats. Chemical cystitis was induced by intravesical instillation of hydrochloric acid in 32 rats, and the treatment group (n =15) received daily 0.4 mg/kg of tamoxifen citrate with orogastric tube, and the control group (n = 17) received no treatment. The sham group consisted of five rats having no acid instillation and no treatment. Cystometric studies were performed in all rats at the beginning and end of the experiment. The rats were euthanized at 2 months. The bladders were removed and examined histologically for mast cells, inflammatory cells, and ER beta. Results: The mean maximal bladder volume increased by 73.6% +/- 25.2 in the treatment group and decreased by 7.2% +/- 10.8 in the control group, revealing a significant difference (P = 0.007). The mean bladder compliance increased by 81.2% +/- 25.2 in the treatment group and decreased by 4.8% +/- 12.7 in the control group, revealing a significant difference between the two groups (P = 0.005). ER beta positive cells were significantly lower in the bladders with chronic cystitis than in the sham group (P = 0.038). Conclusions: Tainoxifen citrate may be an alternative choice, as easy, to other treatment options in the treatment of chronic inflanmnatory condition to improve deteriorated bladder function. In addition, ER beta may have a role on chronic bladder inflammation in a rat chemical cystitis model.