Effects Of Dehydroepiandrosterone On The Proliferation Of Vascular Smooth Muscle Cells Of Male Rats And Its Preliminary Mechanism

Objective:That morbidity of coronary heart disease in woman was higher than that in man was an unambiguous fact, so the investigations about the cardiovascular protective of estrogen became a research hot point that many scholars studied. Many investigations tried to elucidate its protective mechanism. Since estrogen had the vasoprotective role in woman, whether androgen from male body had protective roles on cardiovascular system or not became a question for discussion. Recent years study suggested androgen, mainly testosterone-like androgen had a favorable or neutral role in cardiovascular system in man. Dehydroepiandrosterone (DHEA), the prebody of sex hormone was regarded a kind of androgen. Most study showed DHEA had antiatheroslerotic and anti-CHD roles in man.The proliferation of vascular smooth muscle cells which were one of the major constituent cells of fiber plaque was viewed as one of the pathological characteristics of AS. Many activated factors and signaling transduction paths involved in and regulated the process. Many researches suggested that intercellular adhesion molecule-l(ICAM-l), Angiotensin n type 1 receptor(ATi) and platelet derived growth factor(PDGFR- 3 ) related tightly with proliferation of VSMCs.Based on the few study of DHEA action on VSMCs proliferation and regulated factors, the investigation aimed at the effects DHEA onproliferation of VSMCs and intercellular adhesion molecule-1 (1CAM-1), Angiotensin II type 1 receptor(AT1) and platelet derived growth factor(PDGFR-@ ), primarily discussed the possible mechanism of effects of DHEA on VSMCs proliferation and provided part of the cellular and molecular theory basis of vasoprotective roles of DHEA.Methods:1. Vascular smooth muscle cells, were cultured with the blocks explanting method. VSMCs from passage 3-6 were stimulated for 24 hours by different level DHEA, ER and AR antagonists. MTT technique was used to determine VSMCs proliferation.2. VSMCs from passage 3-6 were stimulated for 24 hours by 10-8 M DHEA. VSMCs were lysed and the concentration of protein was measured using Coomassie blue G250 staining technique. PDGFR- 3 protein expressions were determined by Western Blotting.3. VSMCs from passage 3-6 were stimulated for 24 hours by 10-8M DHEA. Total RNA was eluted. RT-PCR technique was used to measure the relative value of ATi mRNA. VSMCs were lysed by cell lysis buffer and the concentration of protein was measured using Coomassie blue G250 staining technique. ATi protein expression was determined by Western Blotting.4. VSMCs from passage 3-6 were divided 3 groups: 1.Group blank, 2.control(10ng/ml TNF-alpha), 3.Group DHEA stimulating(10ng/ml TNF-alpha +10-8M DHEA). Three groups were stimulated for 24 hours. Total RNA was eluted. RT-PCR technique was used to measure the relative value of ICAM-1 mRNA. VSMCs were lysed by cell lysis buffer and the concentration of protein was measured using Coomassie blue G250 staining technique. ICAM-1 protein expression was determined by Western Blotting.Results:1. 10-10M DHEA evidently stimulated VSMCs proliferation. 10-8M DHEA inhibited VSMCs proliferation. 10-6M DHEA had no effect on it. Neither ER nor AR receptor antagonist could alter the effect of DHEA on proliferation.2. 10-8M DHEA inhibited the expression of PDGFR-beta protein.3. 10-8M DHEA inhibited the expression of VSMCs AT1 mRNA and protein.4. 10-8M DHEA inhibited the expression of VSMCs ICAM-1 mRNA and protein.Conclusions:1. Moderate level DHEA inhibited VSMCs proliferation. DHEA acted on VSMCs proliferation probably not via ER and AR.2. Moderate level DHEA inhibited PDGFR-P protein expression.3. Moderate level DHEA inhibited the expression of AT1 mRNA and protein.4. Moderate level DHEA inhibited the expression of ICAM-1 mRNA and protein.