[Effects of sex hormones on bladder function and structure: experiment with ovariectomized female rats].

OBJECTIVE: To investigate the effects of sex hormones on bladder and mechanism thereof. METHODS: Sixty mature female SD rats underwent bilateral ovariectomy and then randomly divided into 6 groups: low dose estrogen group (OVX + E group) treated with estradiol benzoate 0. 25 mg/kg injected intramuscularly qod, high dose estrogen group (OVX + E 1 mg group) treated with estradiol benzoate 1 mg/kg, progesterone (P) group, treated with P 1 mg, OVX + E + P group treated with estradiol benzoate 0.25 mg/kg + progesterone 1 mg, d androgen group (OVX + T group) treated with testosterone propionate 3 mg/kg, and untreated ovariectomized group (OVX group) receiving no medication. Another 10 rats underwent sham operation. Four weeks later the rats were killed with their bladders and urethras taken out to undergo light and electron microscopy. RESULTS: The thickness of bladder wall of the OVX group was (0.97 +/- 0.11) mm, significant thinner than that of the sham operation group [(1.10 +/- 0.1) mm, P < 0.05)]. The thickness levels of bladder walls of the OVX + E and OVX + T groups were (1.23 +/- 0.12) mm and (1.26 +/- 0.12 mm) respectively, both significantly thicker than that of the OVX group (both P < 0.01). Wider spaces between the detrusor muscle fascicles and degeneration of detrusor muscle cells were seen in the bladder walls of the OVX group, and such phenomena were milder in the OVX + E and OVX + T groups, however, wider spaces between the detrusor muscle fascicles could be seen in the OVX + E + P group too. The hypertrophic effect on the detrusor muscle of the OVX + E 1 mg group was weaker than that of the OVX + E group, a lot of cytoplasmic vacuoles was seen in the 2 groups treated with E, especially the OVX + E 1 mg group. The bladder structure of the OVX + P group was similar to that of the OVX group. CONCLUSION: Endogenous testosterone level as well as estrogen level can significantly affect the bladder structure with a hypertrophic effect on bladder detrusor muscle. But higher doze of estrogen also has some unexpected effects which may destroy bladder structure. In addition, progesterone can compromise the effect of estrogen.