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目的建立人中分化结肠腺癌细胞裸鼠皮下移植瘤模型,以探讨碘-125(125I)粒子治疗中分化结肠腺癌的有效性。方法将人中分化结肠腺癌细胞(SW480)种植到雄性BALB/c-nu/nu裸小鼠皮下,建立动物模型,用随机抽签法随机将荷瘤裸小鼠分成对照组和实验组(每组24只),对照组植入1颗空白粒子,实验组植入1颗剂量为1.48×107Bq的125I粒子,观察粒子植入后瘤体生长情况,分别于植入后第7、14、21及28天处死实验组与对照组荷瘤裸小鼠,每个时相6只裸小鼠。剥取瘤体,分别用于免疫组化SP法测定增殖细胞核抗原(PCNA)的表达,原位末端标记(TUNEL)法检测肿瘤细胞凋亡情况。结果随着放射时间的延长,从第10天起实验组肿瘤体积明显小于对照组(P<0.05),从第14天开始PCNA标记指数表达显著低于对照组(P<0.05),从第21天开始凋亡指数显著高于对照组(P<0.05)。结论 125I粒子通过持续低剂量辐射后可以下调PCNA的表达,诱导人中分化结肠腺癌细胞凋亡增加,是其抑制人中分化结肠腺癌增殖可能的生物学机理之一。
Objective To establish a human subcutaneous xenograft model of human colon adenocarcinoma in order to investigate the effectiveness of iodine-125 (125I) in the treatment of differentiated colon adenocarcinoma. Methods Human subcutaneous adenocarcinoma cells (SW480) were subcutaneously implanted into male BALB / c nu / nu nude mice. Animal models were established. The randomized nude mice were randomly divided into control group and experimental group Group, 24 rats in each group). One control group was implanted with one blank particle. One experimental group was implanted with 125I particles of 1.48 × 107Bq. The growth of the tumor was observed after implantation. And the tumor-bearing nude mice in experimental group and control group were killed on day 28, each time 6 nude mice. The tumors were removed and used to detect the expression of proliferating cell nuclear antigen (PCNA) by immunohistochemical SP method. The apoptosis of tumor cells was detected by TUNEL method. Results With the extension of radiation time, the tumor volume of the experimental group was significantly smaller than that of the control group from day 10 (P <0.05), and the expression of PCNA marker index was significantly lower than that of the control group from day 14 (P <0.05) The apoptotic index at the beginning of day was significantly higher than that of the control group (P <0.05). CONCLUSION: 125I particles can down-regulate the expression of PCNA through continuous low-dose radiation and induce the apoptosis of human differentiated human colon adenocarcinoma cells, which may be one of the biological mechanisms that may inhibit the proliferation of human colon adenocarcinoma.