Effects Of Simvastatin On Rapamycin-treated Cardiac Microvascular Endothelial Cells

Background and objectiveCoronary heart disease (CHD) is the most common and important vascular disease. At the same time, as "the first killer" to human health, it has spread worldwide, becoming a major disaster in many developed countries. The essence of coronary heart disease is myocardial ischemia. Myocardial ischemia and hypoxia are caused by different levels of coronary lumen stenosis or obstruction, then lead a series of clinical symptoms (such as chest tightness, angina), even myocardial infarction or life crisis. Therefore, to maintain vascular patency and ensure the myocardial blood supply is the most critical. Today the treatment of coronary heart disease can be divided into drug treatment, medical intervention and surgical treatment. Medical intervention and drug combination therapy are the main treatments to CHD.There are more than 30 years since the application of medical intervention, technology of which has been fully developed and become the primary means of treatment of CHD. Currently, drug-eluting stent (DES) has replaced the original bare metal stent (BMS) and occupy the major market of medical intervention. Take the rapamycin (RAPA) stent for example, after the implantation of stent, the RAPA(antitumor drug) will be released through a special control of polymer coating. This drug can inhibits proliferation and migration of vascular endothelial and smooth muscle cells, to achieve the objective of reducing restenosis rate.In addition, long-term drug treatment is the essential components of CHD patients. Statins are HMG-CoA reductase inhibitors, which are the conventional drug treatment of CHD. At the same time, statin is a kind of pleiotropic drug. In addition to lowering blood lipid effects, it can also promote endothelial cell proliferation and migration, induced nitric oxide (NO) synthesis and release, inhibits cell apoptosis, have anti-inflammatory and other effects. In our experiment, we taked simvastatin (SIM) as an example, and the cardiac microvascular endothelial cells (CMECs) which have very important function in material exchange were chose to be studied object. We observed the effects of SIM on RAPA-treated CMECs.MethodsPart I: Effects of RAPA on CMECs1. CMECs were isolated from Sprague-Dawley rat left ventricle and cultured.2. CMECs were randomly divided into 5 groups, and then were added with RAPA at the concentration of 0, 0.01, 0.1, 1 and 10μg/L respectively for 24 hours.3. MTT and transwell were used to detect the cell proliferation and migration.4. The concentration (1μg/L of RAPA) was then chosen for the next experiment.Part II: Effects of SIM on RAPA-treated CMECs1. CMECs with RAPA 1μg/L were added with SIM at the concentrations of 0.01, 0.1, 1 and 10?mol/L respectively and cultured for 24 hours.2. The proliferation and migration were detected by MTT and transwell. The secretion of NO was assessed by Griess reaction and the morphological assessment of apoptosis was performed by Hoechst 33258 staining.Results1. CMECs with endothelial cells feature were cultured successfully in vitro.2. Various concentrations of RAPA could inhibit the proliferation and migration CMECs, and the effect was concentration dependent, which meaned that the higher the concentration, the stronger its inhibition. The concentration (1μg/L) of RAPA was then chosen for the next experiment.3. SIM group (1μmol/L) could promote the proliferation and migration of CMECs, inhibit apoptosis, promote NO synthesis and secretion.4. After adding SIM to the CMECs with RAPA(1μg/L), it could improve the inhibition of RAPA on cell proliferation and migration. The most significant improvement effect to inhibition of the proliferation and migration were in the concentration of 1μmol / L and 0.1μmol / L. However,the most obvious improvement effect was showed in the concentration of 10μmol / L. When the concentration was less than 1μmol/L, it showed dose-dependent, which meaned that the higher the concentration, the stronger its improvement; and it did not show significant improvement effect when the concentration got more than 1μmol/L.5. The apoptosis rate was increased in the single RAPA group(1μg/L), and adding SIM could improve the induction of apoptosis. The most significant improvement effect was in the concentration of 1μmol / L.6. RAPA can inhibit the NO synthesis and secretion of CMECs, while SIM could improve the inhibition.ConclusionRAPA is a kind of anticancer drugs, which could significantly inhibit the proliferation and migration of CMECs and show the dose-dependent. In addition, it could also induce CMECs apoptosis, inhibit NO synthesis and secretion and have some impaired effects on CMECs.SIM(1μmol/L) could promote the proliferation and migration of CMECs, inhibit apoptosis, promote NO synthesis and secretion. By adding different concentrations of SIM to the RAPA-treated CMECs and being incubated for 24h, it could improve the inhibition of RAPA, and reduce the rate of apoptosis, thus protect CMECs from these impaired effects via RAPA.