Effects of progesterone/progestin on the apoptosis of the human umbilical vein endothelial cell

Ryu, Ki Young; Park, Young Joon; Kwon, Hee Sun; Na, Young Jeong; Cho, Soo Hyun; Cho, Sam Hyun; Hwang, Youn Yeung

Abstract

OBJECTIVE
The addition of progesterone/progestin is mandatory in women with intact uterus for postmenopausal hormone replacement therapy. However, debate is continuing on whether there is an impact of progesterone/progestin on the hormone replacement therapy for cardiac protection. The aim of this study was to investigate the effect of progesterone/progestin and combination with estrogen on the apoptosis of vascular endothelial cells, which has been demonstrated to be an initial step in the development of atherosclerosis. MATERIAL AND METHODS: Human Umbilical Vein Endothelial Cells (HUVEC) were cultured. HUVEC apoptosis was induced by Tumor Necrosis Factor-alpha (TNF-alpha) (50 ng/ml). 10-7M of estradiol (E2), progesterone (P4), medroxyprogesterone acetate (MPA) and norethindrone acetate (NETA) were added in to the culture media. The percentage of apoptotic HUVEC were measured by 3-[4,5-Dimethylthiazol-2-yl]-2,5- diphenyltetrazolium bromide (MTT) assay and Fluorescence Activated Cell Sorting (FACS) analysis.
RESULTS
MTT assay demonstrated a significant decrease in percent of survival cells after 24 hours of TNF-alpha exposure and a reversal of the effect of TNF-alpha with E2 treatment. P4, MPA and NETA treatment also reversed the effect of TNF-alpha. The protective effect of E2 and P4 were not different. Compared to the E2 treatment, the percent of survival cell were decreased when P4, MPA and NETA were added to E2 treatment, respectively. Similarly, FACS analysis revealed 44.0+/-2.6% apoptosis after 24 hours of TNF-alpha exposure. Treatment with E2 resulted a significant decrease (28.4+/-2.9%, P<0.05) in apoptosis. P4 (33.6%+/-2.6%, P<0.05), MPA (35.7+/-1.3%, P<0.05), NETA (34.0+/-3.3%, P<0.05) treatment also showed a reduction of cell death. The percent of apoptotic cells between E2 and MPA treatment was significantly different. The addition of P4 (36.0+/-2.5%), MPA (36.3+/-1.9%) and NETA (37.0+/-2.0%) to E2 treatment significantly increased the percent of apoptotic cells compared to those of E2 treatment.
CONCLUSION
These results suggested that not only estradiol, but also progesterone, MPA and NETA inhibited HUVEC apoptosis. But the effect of estrogen on the inhibition of HUVEC apoptosis was attenuated in combination treatment of estrogen and progesterone/progestin.