[The changes of sex steroid receptors and morphology in Norplant treated endometrium]

To study the relationship between the changes of sex steroid receptors as well as endometrial morphology and abnormal uterine bleeding induced by Norplant.

Immunohistochemistry, Western Blot, in situ hybridization and computer image analysis were employed to demonstrate the expression of estrone receptor(ER) progesterone receptor(PR) protein and mRNA as well as morphometric analysis of the endometrium in Norplant users.

The content of DNA and the numbers of spiral arterioles decreased in Norplant treated endometrium. The percentage of glandular area in Norplant endometrium was much lower than that in cyclic endometrium. A statistically significant correlation was observed between the percentage of area of glands and abnormal uterine bleeding, as well as serum estrogen(E2) level, but E2 level had no direct relationship with the bleeding abnormality. As the time growing, the percentage of glandular area increased. Immunostaining and relative concentration of glandular and stromal ER in Norplant treated endometrium were significantly weaker and less than all the stage of cyclic endometrium. However, PR, especially stromal PR immunostaining was very intense, which was the same or more than that in all the stage of cyclic endometrium. In situ hybridization detected that the ER and PR mRNA was lower in Norplant treated endometrium than that in cyclic endometrium. The ER mRNA expression was more less abundant than PR mRNA expression.

These results suggested that poor repair and regeneration of endometrium(especially glands and spiral arterioles) and abnormal expression of ER and PR may be related to pathogenesis of abnormal uterine bleeding induced by Norplant implant.