绿茶提取物EGCG对人肺腺癌细胞株A549移植瘤血管超微结构的影响

Effect of green tea extract EGCG on vascular microstructure of human lung adenocarcinoma cell line A549 transplanted tumor

目的以绿茶提取物表没食子儿茶素没食子酸酯(EGCG)干预人肺腺癌细胞株A549裸鼠皮下移植瘤模型,观察其对实体肿瘤微血管结构的影响。方法建立A549荷瘤裸鼠移植瘤模型,随机分为实验组及空白组,分别给予裸鼠EGCG和生理盐水腹腔注射,处理9 d后处死裸鼠并剥离移植瘤,通过量子点双标免疫荧光标记CD31与α-平滑肌肌动蛋白(α-SMA),以观察肿瘤微血管内皮细胞及周细胞表达,并通过计数CD31-微血管密度(MVD)、α-SMA-MVD,计算周细胞覆盖率(MPI);量子点双标免疫荧光标记CD31与四型胶原蛋白(CollagenⅣ),记录CollagenⅣ的表达量,并观察肿瘤微血管的基底膜形态结构;通过透射电镜评价内皮细胞、周细胞的形态与连接、基底膜的完整性以及肿瘤细胞与血管的关系。结果实验组中肿瘤组织CD31-MVD下降,MPI上升,CollagenⅣ总表达量下降,微血管基底膜变薄且规律分布,透射电镜示血管壁内皮细胞较前完整,周细胞较前增多,且与内皮细胞贴合更紧密。结论 EGCG对非小细胞肺癌移植瘤肿瘤微血管生成具有抑制作用,其超微结构改变特点提示血管结构有向正常结构转化趋势。

Objective To observe the effect of green tea extract epigallocatechin gallate (EGCG)on the microvascular structure of human lung adenocarcinoma cell line A549in nude mice.Methods A549tumor- bearing nude mice were randomly divided into an experimental group and a blank group.The mice were injected EGCG and normal saline intraperitoneally.After 9days of treatment,the transplanted tumors were removed from the mice.Microvascular endothelial fineness was observed by quantum dot double-labeled immunofluorescence labeling of CD31and u-smooth muscle actin (α-SMA).CD31-microvessel density (MVD),α-SMA-MVD,and microvessel pericytes coverage index (MPI)were counted,and CD31and Collagen IV were labeled by double- labeled immunofluorescence quantum dots (QDs).The morphology and connection of endothelial cells and pericytes,the integrity of basement membrane and the relationship between tumor cells and blood vessels were evaluated by transmission electron microscopy.Results In the experimental group,CD31-MVD was decreased, MPI was increased,the total expression of Collagen IV was decreased,and microvascular basement membrane became thinner and regularly distributed.Transmission electron microscopy showed that the vascular wall of endothelial cells was more intact than before,more pericytes than before,and adhered to the endothelial cells more closely.Conclusion EGCG can inhibit the angiogenesis of non-small cell lung cancer xenografts.The ultrastructural changes of EGCG suggest that the vascular structure tends to transform to normal structure.