中文摘要：

目的观察微小RNA-15b（miRNA-15b）对人脑胶质瘤细胞株U87细胞侵袭能力的影响。方法体外培养U87细胞,分为空白对照组、阴性对照组和miRNA-15b寡聚核苷酸拟似物处理组（miRNA-15b组）。实时荧光定量PCR检测miRNA-15b表达水平,Transwell小室实验检测细胞侵袭能力,Western blot实验检测细胞侵袭相关蛋白Ras相关C3内毒素底物1（Rac1）和Rac3表达水平。结果脂质体转染U87细胞48h后,miRNA-15b组细胞miRNA-15b相对表达量高于阴性对照组和空白对照组（18.47±2.31vs.12.75±1.98和11.22±1.32）（P〈0.05）;miRNA-15b组细胞穿过人工基底膜数少于阴性对照组和空白对照组[（11.0±1.8）个vs.（34.0±5.1）个和（32.0±4.8）个]（P〈0.05）;miRNA-15b组U87细胞中Rac1和Rac3蛋白表达水平较阴性对照组和空白对照组下降（P〈0.05）。结论 miRNA-15b可通过下调Rac1和Rac3蛋白表达抑制U87细胞的侵袭能力。

英文摘要：

Objective To investigate the effect of microRNA-15b（miRNA-15b）on the invasion ability of glioma U87 cells in vitro.Methods The human glioma U87 cells cultured in vitro were divided into three groups of A（treated with miRNA-15 b mimics）,B（negative control）and C（blank control）.The expression level of miRNA-15 bwas detected by RT-PCR.Transwell assay was used to determine the invasion and migration abilities of U87 cells.The expressions of cell invasion-related proteins Rac1 and Rac3were examined by Western blot.Results Compared to groups of B and C,the expression level of miRNA-15 bwas higher in group A（18.47±2.31 vs.12.75±1.98 and 11.22±1.32）（P〈0.05）.The members of the cells acrossed the artificial basement membrane was less in group A than those in groups of B and C[（11.0±1.8）pieces vs.（34.0±5.1）pieces and（32.0±4.8）pieces]（P〈0.05）.The expression levels of Rac1 and Rac3proteins were lower in group A than those in groups of B and C（P〈0.05）.Conclusion miRNA-15 bcan inhibit the ability of glioma U87 cells in vitro probably via the down-regulation of Rac1 and Rac3expressions.