氧化低密度脂蛋白对血管平滑肌细胞TLR4和Emilin1表达的影响

目的观察氧化低密度脂蛋白（OX—LDL）对大鼠血管平滑肌细胞（VSMCs）TLR4和Emilin1表达的影响及转化生长因子-β（TGF-β）在其中所起的作用。方法将传至2—4代的大鼠VSMCs，用不同浓度的OX—LDL（20、50、80、100μg／m1）干预，采用RT—PCR检测TLR4和Emilin1mRNA表达变化。另设1001μg／ml ox—LDL＋TGF-β（0．01、0．1、1、10tzg／1）培养24h，采用RT—PCR检测TLR4mRNA表达。结果（1）用四种不同浓度梯度的OX—LDL作用后的VSMCs，TLR4和Emilin1在mRNA水平均比空白对照组表达增加，并且呈浓度依赖性。（2）不同浓度TGF-β（0．01、0．1、1、10ng／1）作用后的OX—LDL组（100μg／ml）TLR4mRNA表达明显下降，且呈浓度依赖性。结论OX—LDL可诱导大鼠VSMCsTLR4和Emilin1的表达，促进炎症的发展，OX—LDL可通过使VSMCsEmilin1表达增高途径抑制TGF-β的表达，最终达到促进TLR4高表达的目的。OX—LDL对TGF-β的抑制作用是上调VSMCsTLR4表达的重要途径之一。

Objective To examine the effects of oxidized - low density lipoprotein （ ox - LDL） and transforming growth factor -β on expressions of Toll -like receptor 4（TLR4） and Emilin1 in cultured rat vascular smooth muscle cells （VSMCs）. Methods Rat VSMCs were incubated with different concentrations of ox - LDL（20,50,80,100μg/ml） ,TLR4 and Emilin1 mRNA expressions were detected by RT -PCR. The second group was incubated with different concentrtions of TGF - βand ox - LDL （ 100μg/ml ）. Results The mRNA expressions of TLR4 and Emilin1 were concentration - dependently increased after VSMCs were stimulated by diferent concentrations of ox - LDL for 24h,and the mRNA expressions of TLR4 were concentration - dependently decreased after VSMCs were stimulated by diferent concentrations of TGF -βand ox - LDL（100μg/ml） for 24h. Conclusions Ox - LDL could increase the expression activities of TLR4 and Emilin1 promotes the inflarmnatory progress. It decreases the TGFβexpression, then up -regulates the expression of TLR4 by increasing the expression of Emilin1, which is a main path for un - regulating VSMCs TLR4＇s expression.