Protective Effects Of Captoril On Expression Of Intercellular Adhesion Molecule-1 In Human Umbilical Vein Endothial Cells After Anoxia Reoxygenation

Ischemic preconditioning is called that brief, transient episodes of ischemia myocardium become more resistant against a subsequent severe ischemic insult. This phenomenon was first described by Murry and co-workers.A variety of potential mechanisms have been proposed:adrenergic stimulation, activation of adenosine receptors, opening of KATP channels, indution of heat shock proteins, and induction of oxidative stress. Numerous studies have been performed to demonstrate that in addition to protecting myocytes, preconditioning also protects coronary endothelial cells(ECs) against ischemia-reperfusion injury. Reperfusion injury to the endothelium is mediated by neutrophils that accumulate early after reperfusion in the previously ischemic cardiac tissue. This adhesion is made possible by the expression of adhesion molecules such as intercellular adhesion molecule-1(ICAM-1). Thus the present study was designed to investigate the effect of captoril on expression of ICAM-1 in cultured human umbilical vein endothelial cells(HUVECs) subjected to prolonged anxia followed by reoxygenation, and further research the mechanism of effect of captoril on production of ICAM-1. Methods To establish anxia-reoxygenation model on HUVECs , the third passage of cultured ECV304 was randomly divided into 7 groups: nomal cultured HUVECs (C);anoxia-reoxygenation (H/R), cultured HUVECs were subjected to 2-hour anoxia followed by 6-hour reoxygenation;Captoril (CAP),preconditioning was induced by captoril(10-2mol/L,10-3mol/L,10-4mol/L), after captoril PC for 24-hour cultured HUVECs were subjected to 2-hour anoxia followed by 6-hour reoxygenation; captoril+bradykinin β2 receptor inhibitor(HOE140), captoril+PKC inhibitor (Chelerythrine) ,captoril+NOS inhibitor(L-NAME),captoril+NF-κB receptor inhibitor(PDTC). HOE140, Chelerythrine, L-NAME,PDTC were put into cultured liquid 30-minute before captoril PC. The expression levels of ICAM-1 were quantified by flow cytometer. Results Prolonged anxia followed by reoxyge-nation only moderately affected cell survival(control: 96.5±0.5%;H/R87.8±1.0%;n=3;P<0.05). Captoril precondi- tioning slightly increased survival as compared with untreated H/R (CAP: 93.4±0.8%;n=3;vs H/R P<0.05).The levels of expression of ICAM-1 was higher in H/R group (10.2±0.6) than C group(3.9±0.5) (P<0.05),lower in CAP group(10-2mol/L)(5.9±0.3) than in H/R group (10.2±0.6) (P<0.05),however higher in four inhibitor groups than in CAP group(P<0.05). Discussion The main results of our study, performed in cultured ECs, are that (1)H/R markedly increased the endothelial expression of ICAM-1,(2)ICAM-1 expression were markedly reduced by Captoril preconditioning, but four inhibitor could abolish function of Captoril preconditioning. Captoril is an angiotensin converting engyme (ACE) inhibitor. ACE, an enzyme located in the endothelial cell membrane, activates angiotensin Ⅰ and angiotensin Ⅱ, and deactivates bradykinin. Bradykinin activates endothelial bradykinin(β2) receptors, which results in the formation nitric oxide and prostacyclin. Hence, ACE inhibitor not only prevent the formation of angiotensin Ⅱ,but also increase the local levels of bradykinin and in turn nitric oxide and prostacyclin. These compounds are vasodilators and potent inhibitors of platelet function,and therefore may mediate important protective effects of ACE inhibitor. Bradykinin β2 receptor inhitor (HOE140) and NOS inhibitor (L-NAME) could abolish function of Captoril preconditioning. These suggest that the protective effect of Captoril preconditioning is the function of Bradykinin and nitric oxide. Captoril possesses an sulfhydryl group on the cellular redox state (monitored by measuring intracellular rective oxygen species and thiol status).H/R increased the activation of NF-kappaB, but Captoril dependently decreased its activation. Conclusion The expression of ICAM-1 was increased in anxia-reoxygenation, captoril can decrease the expression of ICAM-1. This finding indicates that t...