Effects And Their Possible Mechanisms Of Puerarin And Quercetin On The Proliferation Of Cultured Human Thoracic Aortic Smooth Muscle Cells In The High Glucose And High Insulin Medium

Insulin resistance (IR), characterized by the target organs or tissues insensitivity to insulin, is a common pathological status of cardiovascular diseases and diabetes. Accompanied with IR, the high blood glucose and high insulin are the main reasons of abnormal proliferation of vascular smooth muscle cells (VSMCs). There are two important signal transduction pathways involved in the cell proliferation induced by insulin, including mitogen activated protein kinase (MAPK) pathway and phosphatidylinositol-3 kinase (PI3K) - protein kinase B (PKB) - mammalian target of rapamycin (mTOR) pathway. PD98059 is a specific inhibitor of MAPK. PI3K becomes the focus on the effects of cell growth and cell proliferation by nutrition uptaking and cell cycle regulation. LY294002 is a specific inhibitor of PI3K which produces biological effects at macro-moles level. PKB is a direct downstream signal molecule of PI3K. Three kinds of distinct PKB isoforms have been identified. PKBα plays an important role in cell growth and proliferation. Recently, it suggested that activated PI3K-PKB pathway may induce cell proliferation by increasing the phosphorylation and the expression of downstream signals of mTOR and by promoting cell cycle.Puerarin (PU), a flavonoid, is the major effective ingredient extracted from radix puerariae belonged to leguminous plants, which can improve microcirculation, dilate coronary artery, increase blood flow of brain and coronary artery, decrease blood pressure, and raise the amount of high density lipoprotein. PU is extensively used for patients with coronary artery diseases, hypertension and hyperlipemia. Quercetin (QU), a flavone frequently existed in nature, is a specific tyrosinase inhibitor. QU has been reported to be effective in decreasing blood pressure, regulating blood lipid, inhibiting tumor growth, etc. It is confirmed that PU and QU have a variety effects including diminishing blood glucose, improving insulin sensitivity and glucose...