The role of estrogen receptor subtypes for induction of delayed effects on the estrous cycle and female reproductive organs in rats

Comparative study of DHEA and letrozole induced polycystic ovary syndrome in post-pubertal rats

AIM

In order to select a suitable rat model for studying polycystic ovary syndrome (PCOS).

METHODS

Post-pubertal Sprague Dawley (SD) rats were allocated to four groups, abbreviated as the control 1 group, DHEA subcutaneous injection (DHEA) group, control 2 group, letrozole intragastric injection (letrozole) group. Body weight and the estrous cycle were monitored during the modeling. Serum stress hormones and reproductive hormones were evaluated by ELISA. The uterus and ovaries were weighed, ovarian follicle counts were calculated, and AR, LHR, FSHR, and AMH expression were assessed by immunohistochemistry.

RESULTS

In both model group subjected to the 30-day protocol of DHEA or letrozole, the mean body weights were significantly increased. Rats from both model group exhibited a significant increase of the mean length of the diestrous phase of the estrous cycle, the DHEA group had a longer diestrous phase. There was also a significant increase of serum T, E2, LH, insulin, and a significant decrease of AMH in both model group. There was a significant decrease of ovarian weight, P, and serum FSH, and a significant increase of uterus weight, serum LH/FSH in DHEA model group. There was no significant difference in serum P, FSH, and LH/FSH in letrozole model group. Both two model groups showed significantly higher AR, LHR, and AMH protein expression in rats' ovaries. FSHR protein expression in DHEA group was lower, and in letrozole model group was not different.

CONCLUSION

Compared with letrozole intragastric injection group, the pathological characteristics of DHEA subcutaneous injection group rats were closer to the characteristics of PCOS.