中文摘要：

目的观察LDL刺激下大鼠系膜细胞的增殖情况和COX-2 mRNA和蛋白表达水平的变化。探讨COX-2表达和LDL、系膜细胞增殖之问的关系。方法以体外培养的大鼠系膜细胞为研究对象。应用不同浓度的LDL刺激系膜细胞。应用MTT法检测细胞增殖；应用KT-PCK和Westem Blot的方法检测COX-2 mKNA和蛋白的表达。分析COX-2 mRNA和蛋白的表达与LDL浓度、系膜细胞增殖的相关性。结果以浓度为3．125-100．000μg／mL的LDL刺激系膜细胞，可促进系膜细胞的增殖，在LDL 0．000-50．000μg／mL的浓度范围内，系膜细胞的增殖和LDL的浓度呈正相关；以浓度为3．125-100．000μg／mL的LDL刺激系膜细胞，可上调COX-2 mRNA和蛋白的表达。在LDL0．000-50.000μg／mL的范围内，COX-2 mRNA和蛋白的表达与LDL浓度、系膜细胞增殖呈正相关。结论LDL可以诱导系膜细胞增殖，上调COX-2表达，在LDL 0．000-50．000μg／mL的范围内，系膜细胞增殖与LDL浓度具有相关性，COX-2的表达与LDL浓度、系膜细胞增殖具有相关性。

英文摘要：

[Objective] To observe the proliferation of rat mesangial cells and the expression of cyclooxygenase-2 （COX-2） mRNA and protein induced by low-density lipoprotein （LDL）, and to explore the possible correlations of the expression of COX-2 and concentration of LDL, the proliferation of mesangial ceils. [Methodsl Cultured rat mesangial cells were performed with LDL of different concentration in vitro. Cell viability was measured by MTr as- say; the expression of COX-2 mRNA and protein was measured by RT-PCR and Western Blot. The possible correlations of the expression of COX-2 and concentration of LDL, the proliferation of mesangial cells were analyzed. [Results] The proliferation of mesangial cells were promoted by LDL of the concentration from 3.125 to 100.000 μg/mL, when the LDL concentration was from 0.000 to 50.000 μg/mL, the proliferation of mesangial cell was correlated with LDL concentration. The expression of COX-2 mRNA and protein were upregulated by LDL of the coneentration from 3.125 to 100.000 μg/mL, when the LDL concentration was from 0.000 to 50.000 μg/mL, the expression of COX-2 mRNA and protein was correlated with LDL concentration and the proliferation of mesangial cell. [Conclusions] The proliferation of mesangial ceils and the expression of COX-2 are induced by LDL, when the LDL concentration is from 0.000 to 50.000 μg/mL, the proliferation of mesangial cell is correlated with LDL concentration, and the expression of COX-2 is correlated with LDL concentration and the proliferation of mesangial cell.