脂多糖对血管平滑肌细胞一氧化氮合酶基因表达及细胞增殖的影响

应用ＲＮＡ印迹分析和亚硝酸盐含量测定检查脂多糖（ＬＰＳ）对大鼠血管平滑肌细胞（ＶＳＭＣ）一氧化氮合酶（ＮＯＳ）基因表达及ＮＯ合成的影响，用３Ｈ－ＴｄＲ参入实验观察ＬＰＳ对细胞ＤＮＡ合成的影响．结果表明，ＬＰＳ在诱导ＶＳＭＣｉＮＯＳｍＲＮＡ表达和促进ＮＯ合成的同时，抑制ＶＳＭＣＤＮＡ合成．证明ＬＰＳ的作用与其浓度和作用时间有关

Effects of LPS on Expression of Nitric Oxide Synthase Gene and Proliferation in Vascular Smooth Muscle Cells

The cultured rat vascular smooth muscle cells(VSMC)were used to study the effects of lipopolysaccharides (LPS)on the expression of inducible nitric oxide synthase(iNOS)gene and its relationship to cell proliferation.With Dot blotting,Northern blotting analysis and measurement of nitrite,the expression of iNOS gene and the synthesis of supernatant nitrite were observed in control and treated VSMC with LPS of different concentration(10,20,50 μg/ml)and the same concentration (10 μg/ml)for different time (6,12,24 hours).It was found that LPS induced iNOS mRNA in VSMC and led to the increase of nitrite in culture medium in a dose dependent manner .iNOS mRNA increased after 6 h exposure to LPS.Abundance of iNOS mRNA peaked at 12 h.The changes of nitrite were the same as the expression of iNOS gene.In the meantime,LPS inhibited the DNA synthesis in VSMC.When VSMC were treated with 20,50 μg/ml LPS for 24 h, 3H TdR incorporation inhibited by 20.5% and 48.7%,respectively.The inhibitory rate of DNA synthesis was greatest in VSMC treated with LPS for 12 h.