Hormone-like activities of Kuntai capsule in the uteri of ovariectomized rats and immature rabbits

Abstract

OBJECTIVE

To investigate the hormone-like activities of Kuntai capsule (KTC) in the uteri of ovariectomized rats and immature rabbits.

METHODS

Following bilateral ovariectomy, rats were randomly divided into six groups including sham group, control group, estradiol valerate group, KTC 0.24, 0.6, and 1.5 g/kg groups. The rats were treated with 0.5% CMC-Na, estradiol valerate and KTC (0.24, 0.6, and 1.5 g/kg), respectively for 28 consecutive days. Then the estrous cycle, uterine changes and pathological changes were examined. Serum levels of estradiol (E2), and progesterone (P4) were measured by enzyme-linked immunosorbent assay (ELISA). Protein levels of estradiol receptor (ER), progesterone receptor (PR), vascular endothelial growth factor (VEGF), proliferating cell nuclear antigen (PCNA) and nuclear-associated antigen-67 (Ki-67) in uterine tissues were detected by western blot. Immature rabbits were estrogen-primed prior to intragastric administration with KTC for 6 d consecutively. Then, the uteri underwent hematoxylin-eosin staining to observe endometrial transformation.

RESULTS

Compared with the control group, 0.6 and 1.5 g/kg KTC markedly decreased the uterine organ coefficient and endometrial thickness (P < 0.05). The serum level of P4 was increased in the KTC 0.6 g/kg group (P < 0.05). There were no significant variations in the serum level of E2 in the KTC groups compared with the control group. ERβ, but not ERα, was markedly upregulated after KTC administration (P < 0.05). Furthermore, 1.5 g/kg KTC significantly decreased the protein level of PRA (P < 0.05) and 0.6 g/kg KTC increased the protein level of PRB in the uteri (P < 0.05). VEGF was highly expressed after treatment with 0.24 and 0.6 g/kg KTC, and Ki-67 was markedly reduced in ovariectomized rats treated with 1.5 g/kg KTC. No difference was found in the expression of PCNA. KTC 0.24 and 0.6 g/kg promoted endometrial transformation in immature rabbit uteri.

CONCLUSION

KTC does not demonstrate obvious estrogen-like effect on uteri after ovariectomy, but it does exhibit weak progestogen-like effect, by which mechanism of action is yet to be further investigated.