低剂量辐射增强化疗药物抑制lewis肺癌转移的实验研究

探讨增强化疗药物抑制恶性肿瘤转移的新的有效方法。采用Ｃ５７ＢＬ／６小鼠右后肢腓肠肌内接种ｌｅｗｉｓ肺癌细胞制成实验动物模型，２１ｄ杀鼠取肺，计数肺转移结节数，观察丝裂霉素Ｃ（ＭＭＣ）化疗前预先７５ｍＧｙＸ射线全身照射对ＭＭＣ抑制肿瘤转移作用的影响。结果显示，单纯的３．０ｍｇ／ｋｇＭＭＣ腹腔注射不能明显减少ｌｅｗｉｓ肺癌的肺转移结节数（对照组：４１．７±７．４／肺，单纯化疗组：３３．８±１１．５／肺，Ｐ＞０．０５）；而化疗前６ｈ给予７５ｍＧｙＸ射线全身照射组肺转移结节数较单纯化疗组明显减少（２０．３±４．７／肺，Ｐ＜０．０５）。免疫学参数测定结果表明，化疗使荷瘤小鼠腹腔巨噬细胞（ＰＭΦ），脾脏自然杀伤细胞（ＮＫ）功能明显下降（Ｐ＜０．０５）；而７５ｍＧｙ＋ＭＭＣ组的免疫学参数较单纯化疗组显著提高（Ｐ＜０．０１）。提示化疗前预先７５ｍＧｙＸ射线全身照射对ＭＭＣ免疫抑制的减轻作用可能是其增强化疗抑制ｌｅｗｉｓ肺癌转移的重要基础。

Low dose radiation in combination with mytomycin C suppresses the mtastasis of Lewis lung carcinoma: An experimental study

To find out a new and effective methold to enhance the efficacy of cytotoxic agents against the metastasis of malignant tumor,we used C57BL/6 mice implanted with Lewis lung carcinoma cells in the right thighs,sacrificing them to count lung metastasis nudles 21 days after implantation as an experimental in situ metastasis animal model.The results indicated that treatment with 30 mg/kg mytomycin C(MMC) I.P. alone could not markedly reduce the number of metastasis nudles in lungs (control group:417±74,MMC treatment alone:338±115,P>005),when whole body irradiation (WBI) with 75 mGy X-rays was given 6 hours before MMC chemotherapy,the number of lung metastasis nudles was much fewer than that with MMC treatment alone (203±47,P<001).The detection of immune parameters showed that MMC treatment significantly suppressed the functions of peritoneal macrophage and natural killer cells (P<005),while the immune function of 75 mGy+MMC group was much higher than that with MMC treatment alone (P<001).These results demonstrated that the protective effect of low dose radiation on the immune system against MMC might be one of the important factors due to this enhanced anti metastasis effecacy of MMC chemotherapy.