血管内皮生长因子基因沉默抑制人胶质瘤裸鼠移植瘤生长及血管生成的研究

Gene silencing of VEGF inhibits growth and angiogenesis of human glioma U251 implanted in nude mice

目的观察靶向血管内皮生长因子（VEGF）的短发夹RNA（shRNA）对裸鼠人脑胶质瘤中VEGF基因表达的抑制作用。方法体外培养人脑胶质瘤U251细胞株，建立人脑胶质瘤裸鼠皮下接种模型。将成功造模的30只裸鼠随机分为A、B、C3组（每组10只），分别给予不同处理。观察肿瘤生长。免疫组织化学检测瘤组织中VEGF蛋白表达及组织内的微血管密度（MVD）改变。结果治疗5周后，VEGF shRNA组（A组）的肿瘤体积为654．0mm^3、抑瘤率达65．2％，与空质粒组（B组）1790．4mm^3、4．7％或PBS组（C组）1880．3mm^3、0％比较，差异有统计学意义（P〈0．05）。A组荷瘤组织中VEGF和MVD分别为9．52、22．02，与B组17．18、43．58或C组17．82、45．32比较，差异有统计学意义（P〈0．05）。VEGF蛋白表达与MVD间存在正相关性（r=0．721，P〈0．01）。结论应用RNAi技术沉默VEGF基因能明显抑制人脑胶质瘤细胞株U251裸小鼠移植瘤的生长。

Objective To explore the inhibitory effect of silencing human vascular endothelial growth factor （VEGF） gene short hairpin RNA （shRNA） on the growth of human glioma in nude mice by RNA interference technique. Methods Human glioma U251 cells, cultured in vitro,were used to establish models of human glioma by subcutaneous injection into nude mice. The 30 mouse models were divided into 3 groups for varied purposes and treatment （n = 10 ）. The VEGF expression and microvessel density （MVD） in tumor tissues were measured by immunohistochemistry. Results The volume and inhibition rate of tumor in the therapy group （group A） was 654.0 mm^3 and 65.2% respectively,compared to 1790.4 mm^3 ,4.7% in the blank plasmid group （group B） ,and 1880.3 mm^3 ,0% in the PBS group （group C） ,with the difference being statistically significant （ P 〈 0.05 ）. Moreover, VEGF and MVD in group A were 9.52, and 22.02,compared to 17.18, and 43.58 in group B, and 17.82, and 45.32 in group C, with the difference being also statistically significant （ P 〈 0.05 ）. There was a positive correlation between VEGF and MVD （r =0.721 ,P 〈 0.01 ）. Conclusion Silencing VEGF gene can decrease VEGF gene expressions, suppress tumor angiogenesis, and inhibit tumor growth in nude mice bearing human glioma cell line U251.