We examined the effect of androgens on bladder blood flow, bladder function, and histological changes in castrated male rats. Male Wistar rats were classified into unoperated group (control group), groups castrated at the age of 8 weeks (group 8wPC), and groups castrated at the age of 4 weeks (group 4wPC). Each rat was used at the age of 20 weeks. Bladder blood flow was measured using fluorescent microspheres. Bladder cystometry was performed without anaesthesia or restraint; the bladder was first irrigated with saline and then with 0.25% acetic acid solution. Maximum voiding pressure and voiding interval were measured. The bladder and iliac artery were histologically examined for differences in smooth muscle and quantity of collagen fibre to analyse the effect of castration on the smooth muscle content. No differences were noted in bladder blood flow following castration. The voiding intervals for all groups were shortened (P < 0.001) following acetic acid irrigation. No significant difference was noted in the maximum voiding pressure. Histological changes were observed in bladder and iliac artery. Smooth muscle/collagen ratio at the bladder was lower in groups 8wPC and 4wPC compared to the control group (P < 0.01); while that at the iliac artery was decreased in group 4wPC compared to the control group (P < 0.001). In conclusion, our findings indicate that castration does not alter bladder blood flow but leads to histological changes in the bladder as well as its associated blood vessels.

Keywords: bladder blood flow; bladder function; castration; fluorescent microsphere method; histological changes; smooth muscle/collagen ratio

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