小鼠结肠癌高转移模型体内筛选和建立

Establishment of a Highly Metastatic Model of Colorectal Cancer in Mice through in Vivo Selection

目的采用体内筛选的方法建立小鼠结肠癌高转移模型,为系统研究结肠癌转移机制和临床结肠癌治疗提供动物模型。方法先将C26小鼠结肠癌移植于T、B、NK免疫细胞缺陷的NOD-SCID小鼠皮下,并在首代筛选过程中切除皮下瘤,延长小鼠寿命以获得明显转移灶,然后通过皮下移植→肺转移→皮下移植→肺转移的体内循环筛选方法建立高转移模型。以建立成功的高转移模型为瘤源,在BALB/c小鼠体内以相同的方法继续筛选,同时进行肿瘤的生长和转移情况观察、病理组织学、超微结构、细胞增殖周期和异倍体的观察。结果NOD-SCID小鼠筛选5代后肺转移达100%。但筛选后的肿瘤组织皮下移植到BALB/c小鼠体内时,肿瘤的转移程度有所下降,又经BALB/c小鼠体内4代筛选,肿瘤的移植成瘤率、肺转移率均为100%。病理组织学、超微结构观察、细胞增殖周期和异倍体等结果表明与原结肠癌生物学特性相似。结论作者建立的肺转移率100%、转移特性稳定、直观性好、操作简便的小鼠结肠癌高移植模型,为探讨结肠癌转移的生物学机制和抗转移治疗提供了理想的动物模型。

Objective To establish a highly metastatic model of colorectal cancer in mice by using organ selection of metastasis. Methods Histologically intact C26 colorectal cancer tissues were subcutaneously implanted into the NOD-SCID mice which is immunodeficiency. In order to gain visible metastatic focus, the tumor bearing mice were undertaken tumor resection in first selection when tumor reached 1.5 cm in diameter. Screening was conducted according to the method of subcutaneous implantation→ lung metastasis → subcutaneous inoculation → lung metastasis. Then the same steps were duplicated in BALB/c mice. Tumorgenicity, invasion, metastasis and morphological characteristics of the implanted tumors were studied by light microscopy, electron microscopy and flow cytometry. Results Highly metastatic models of mice colorectal cancer were obtained after organ screening. After 5 generations in vivo, the carcinoma metastasis rate accounted to 100 percent in NOD-SCID mice, and the metastases of lungs and lymph nodes were noted in all of animals. While only a lower metastasis rate was found when the tumor was subcutaneously implanted in natural mice at the first time. But a 100 percent lung metastatic rate was observed again after being passaged in vivo for 4 generations in natural mice. Conclusions We had established a highly metastasis colorectal cancer model of natural mice which was high, steady, and intuitionistic metastasis and had same biological characteristics of mice colorectal carcinoma. The result provided a useful tool for the study of metastatic mechanism and treatment of human colorectal carcinoma.