Ad．VEGF．siRNA抑制荷人骨肉瘤裸鼠血管生成的形态学研究

背景与目的：血管内皮生长因子是骨肉瘤血管形成重要的促进因子，本研究通过抗血管生成方法，观察其抑制荷人骨肉瘤裸鼠血管生成的形态学表现。方法：取4～8周龄的Balb／c裸鼠作为实验动物，人骨肉瘤细胞株MG63皮下接种法构建骨肉瘤的动物模型。建模成功后将荷人骨肉瘤的裸鼠随机分为3组，每组15只。A组使用自行构建的Ad—VEGF-siRNA干扰新生血管形成；B、C组分别使用等剂量的Ad-EGFP或PBS作为对照。实验维持19d，药物使用后隔日测量肿瘤体积和体重．绘制肿瘤生长曲线：采用常规HE染色、VEGF和CD31相关抗原免疫组化染色观察各组肿瘤标本：各组随机抽取一个标本在透射电镜下观察仿血管发生的超微结构。结果：实验结束时，A组裸鼠瘤体体积为（0．31±0．18）cm^3，重量为（0．75±0．21）g，微血管密度（microvessed density，MVD）为5．79±0．34，VEGF表达为235228．09±123244．41，B、C照组裸鼠瘤体积分别为（1．21±1．29）cm^3、（1．43±0．95）cm^3；瘤重分别为（1．19±0．27）g、（1．19±0．35）g；MVD分别为11．00±0．68、10．42±0．10：VEGF表达分别为9641992．40±90479．62、981298．00±213590．50。A组肿瘤体积、重量、MVD和VEGF表达均显著低于B、C组。MVD和VEGF呈正相关关系，相关系数为0．9989。Ad-VEGF—siRNA组仿血管发生数量1．4000±0．5477，明显小于Ad—EGFP和PBS对照组。透射电镜可见肿瘤细胞形成的仿血管。结论：通过宏观和微观的形态学观察，证实Ad—VEGF-siRNA介导的以VEGF为靶向的抗血管生成能够抑制荷人骨肉瘤裸鼠的血管生成。

Morphological changes in osteosarcoma xenografts in nude mice after inhibiting angiogenesis by Ad-VEGF-siRNA

Background and Objective. Vascular endothelial growth factor （VEGF） is a critical stimulator for angiogenesis of osteosarcoma. This study was to investigate the morphological changes in osteosarcoma xenografts in nude mice after inhibiting angiogenesis by Ad-VEGF-siRNA. Methods： The animal model of osteosarcoma xenografts was constructed by subcutaneous inoculation of osteosarcoma MG63 cells into nude mice. The mice were randomly divided into three groups, 15 mice in each group.- group A and control groups B and C. The tumor nodules were injected with Ad-VEGF- siRNA in group A, an equal dose of Ad-EGFP and PBS, respectively, in groups B and C. The volume and weight of tumors were measured every two days after injection and the growth curves were drawn. The tumor samples were observed and analyzed using HE staining. Angiogenesis was assessed by immunohistochemical staining using anti-VEGF and CD31 antibodies. The ultrastructure of vasculogenic mimicry （VM） was observed using transmission electron microscopy （TEM）. Results： The mean volume,weight, microvessel density （MVD） and VEGF expression of tumors in AdVEGF-siRNA-treated group were significantly lower than those in the control groups. MVD was positively correlatied to VEGF expression, with a correlation coefficient of 0.9989. The number of VM was 1.40±0.55 in the AdVEGF-siRNA group, which was significantly less than those in the two control groups. Conclusion： Ad-VEGF-siRNA could effectively block angiogenesis in osteosarcoma xenografts in nude mice.