Clinical And Experimental Research Of The Effect Of Estrogen On ACE And Vessel Endothelium

Objective: Through investigating the effect of estrogen replacement therapy (ERT) on serum angiotensin-converting enzyme (ACE) and serum lipids in postmenopausal women and on ACE and vessel endothelium in ovariotomized rats, We study the protective mechanism of ERT on cardiovascular system in postmenopausal women. The first part: The effect of ERT on serum ACE and lipids in postmenopausal women. 1.1 Methods: Sixty women with natural menopause were enrolled. 30 of them were treated with livial tablet for 14 weeks while another 30 were treated with placebo and served as control. Before and at the end of the study, the serum levels of estradiol (E2), follicle stimulating hormone (FSH), total cholesterol (TC), triglyceride (TO), high density lipoprotein-cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), lipoprotein a [Lp(a)j and ACE were measured. 1.2 Results: In the control group, the serum ACE and lipids levels changed insignificantly; In the ERT group, E2 level increased, ACE level decreased significantly and showed negative correlation with E2 level. The levels of serum TC, LDL-C and Lp(a) decreased, HDL-C level increased, and there was no significant change in TO level. The second part: The effect of ERT on serum ACE and vessel endothelium in ovariotomized rats. 2.1 Methods: Fifty SD female rats were divided into 5 groups randomly: OVX group, OVX+E group, OVX+NS group (all ovariotomized ), sham group and normal control. Before and at the end of the 14th week, serum ACE and E2 levels were measured. At the end of the 28th week, the VEC changes were assessed under the light microscope and scanning electron microscope. 2.2 Results: For the OVX+E group, serum E2 increased and ACE decreased significantly at the end of the 14th week while there were no such changes in the other four groups. The serum E2 showed negative correlation with ACE in OVX-I-E group, sham group and normal control group while there were no such changes in the other groups. At the end of the 28th week, the VEC were arranged orderly in OVX+E group and normal control group while arranged disorderly in the OVX group. Conclusion: Clinical experiment proved that ERT for menopausal women could decrease serum ACE level and increase serum lipids metabolism; animal experiment proved that ERT for avariotomized rats could decrease serum ACE level and improve the function of vessel endothelium through alleviating the damage on it. Our study indicated that the cardiovascular protective mechanism of ERT in postmenopausal women might include improving serum lipids metabolism, decreasing the serum ACE levels and benefiting the function of vessel endothelium. The three facets interacted with each other and played the role of protecting cardiovascular system cooperatively.