大鼠Walker-256肝微小转移癌模型的建立及病理学、影像学的初步研究

目的建立实验性大鼠Walker-256肝微小转移癌模型并探讨其病理学和影像学特点。方法SD大鼠30只经脾脏注入Walker-256瘤细胞建立大鼠微小肝转移癌模型。在接种瘤细胞第9天行CT检查观察肿瘤生长情况。病理学用HE染色和血管内皮生长因子(VEGF)、微血管密度(MVD)免疫组织化学的方法观察肿瘤的大小、形态及血管化程度。结果SD大鼠30只中有2只麻醉意外死亡,剩余大鼠中随机选取22只处死,有19只肝脏内找到转移灶。转移灶的直径在0.5~6.6mm。转移的成功率为86.4%。CT常规扫描方法对直径小于5mm的转移灶检出率不足10%。病理学病灶符合癌肉瘤的特点。肿瘤内均有VEGF的表达,但程度不同;MVD的数量与VEGF表达程度呈正相关。结论经脾脏注入Walker-256癌肉瘤细胞建立大鼠肝转移癌模型的方法简便易行,成瘤率高。免疫组织化学方法显示微小转移癌灶内有新血管生成,适合影像学功能成像技术与肿瘤血管化程度的对照研究。

Walker-256 small metastasis in rat liver: model establishment, pathologic and imaging study

Objective To establish a model of Walker-256 small metastasis in the liver of rat, and to evaluate the pathological and imaging features and tumor angiogenesis. Methods Thirty SD rats were injected with 2×10⁷ Walker-256 cells into the spleen and the models of metastasis in the liver of rat were established. CT was performed to observe the tumor morphologic features 9 days after the tumor cells injection. The livers of rats were sliced and stained with hematoxylin-eosin. Vascular endothelial growth factor (VEGF) and microvessel density (MVD) were evaluated in immunohistochemacal examination. Results Among the 30 experimental SD rats, 2 died in operation, 22 were killed randomly, liver micrometastasis were found in 19 of the 22 rats, the success rate was 86.4% (19/22). The diameters of tumors were from 0.5 mm to 6.6 mm. Less than 10% of metastasis with the diameter less than 5 mm were showed by CT scan. Pathologic examination showed characteristics of malignant mixed mullerian tumors. VEGF was expressed in all tumors, but the rate of positive cells is different in different tumors. Using Pearson's linear correlation analysis, positive correlation was found between MVD and VEGF. Conclusion A stable model of Walker-256 rat liver small metastasis has been established. Regarding the distribution of MVD, the study showed that MVD was most frequently observed at the marginal region of metastasis. The model is helpful for the pathological and radiological study of tumor angiogenesis.