LDL对小鼠成骨细胞的影响

摘要

Objective To investigate the effect of low density lipoprotein(LDL) on the proliferation and differentiation of mouse osteoblasts and related mechanism. Methods Mouse osteoblasts MC3T3-El were cultured with low density lipoprotein(LDL) at concentration of 0.05, 0. 1 and 0. 2 mg/ml, respectively. The proliferation and differentiation of MC3T3-El osteoblasts were detected with CCK-8 after treated with LDL for 24, 48 and 72 h. The osteocalcin levels were detected by ELISA and the expression of LDL receptor-related protein 5(LRP5) and dickkopf-1 (DKK1), were detected by realtime PCR. Results The proliferation of osteoblasts was significantly suppressed by LDL treatment in a dose-and time-dependence manner (P < 0. 05). ELISA showed that osteocalcin expression was inhibited by LDL with a dose-and time-dependence manner ( P < 0. 05 ). Real-Time PCR results exhibited that expression of LRP5 mRNA was up-regulated and expression of DKK1 mRNA was down-regulated with 0.05 mg/ml LDL for 48 h( P < 0.05). Conclusion LDL can suppress the proliferation and differentiation of osteoblasts, which might be correlated with the up-regulation of LRP5 gene and down-regulation of its antagonist DKK1 gene in the wnt signal passageway.%目的 研究不同浓度及同一浓度不同作用时间的LDL对小鼠成骨细胞增殖分化及LRP5、DKK1表达的影响,探讨Wnt信号通路是否参与了LDL对成骨细胞增殖分化调节.方法 在小鼠成骨细胞株MC3T3-E1培养液中加入0 05、0.1、0.2 mg/ml的LDL,分别培养24、48、72 h后应用CCK8检测其对成骨细胞增殖的影响,采用ELISA法检测成骨细胞骨钙素水平,分析LDL对成骨细胞分化的影响；采用荧光定量PCR方法检测LDL对成骨细胞LRP5、DKK1基因表达水平的影响.结果 在LDL浓度为0.05 mg/ml 24 h时,明显抑制戊骨细胞的增殖,与对照组比较,差异具有统计学意义(P＜0.05).LDL对成骨细胞增殖的作用呈剂量及时间依赖性.ELISA实验结果显示LDL明显抑制成骨细胞中的骨钙素表达,与对照组比较,差异具有统计学意义(P＜0.05).LDL对成骨细胞骨钙素表达的作用在一定程度上具有剂量及作用时间依赖性.荧光定量PCR实验结果显示LDL在48h浓度为0.05 mg/ml时明显下调成骨细胞中的LRP5mRNA表达水平,显著上调DKK1 mRNA表达水平,与对照组比较,差异具有统计学意义(P＜0.05).结论 LDL能够显著抑制成骨细胞的增殖和分化,这可能与wnt信号通路中LRP5及其抑制剂DKK1基因表达有关.