Objective To study the effects of nylestriol, especially the long-term nylestriol use, on the
karyokinesis and the expression
of
proliferating cell nuclear antigen ( PCNA ) of endometrium in postmenopause women. Methods We tested the
karyokinesis and the expression of PCNA of endometrium in 23 short-term and 6 long-term postmenopause women, as well as 9 short-term and 6 long-term nylestriol use postmenopause women, 5 endometrial dysplasia and 5 endometrial cacinoma women. Results There were no differences of karyokinesis and expression of PCNA of endometrium between the short-term and the long-term postmenopause women. The same results could be obtained in the short-term and long-term nylestriol use postmenopause women, as well as short-term postmenopause women and short-term nylestriol use postmenopause women, long-term post-menopause women and long-term nylestriol use postmenopause women. The karyokinesis and the expression of PCNA of endometrium in short-term and long-term nylestriol use postmenopause women were all lower than those in endometrial dysplasia and endometrial cacinoma women. Conclusion Proliferating effect of nylestriol on endometrium was weak. Long-term nylestriol use was safe to the postmenopause women.