Influence of low dose radiation on the pulmonary metastasis of Lewis lung carcinoma in mice

探讨低剂量全身照射对肿瘤转移的影响。方法：采用荷有Lewis肺癌的C57BL／6J小鼠作为实验动物模型。在肿瘤移植后10d，分别给予以下处理：①假照组；②2次75mGyX射线全身照射，间隔3d；③4次75mGyX射线全身照射，间隔3d；④3．0mg／kgMMC腹腔注射化疗；⑤3．0mg／kgMMC腹腔注射化疗前6h预先给予75mGyX射线全身照射。化疗后12h断头处死①、④和⑤组各6只小鼠，测定腹腔巨噬细胞（Mφ）吞噬功能和脾脏自然杀伤细胞（NK）的细胞毒效应。在肿瘤移植后21d，处死全部小鼠取双肺，计数肺转移瘤结节数。结果：单纯MMC腹腔注射化疗组小鼠肺转移瘤结节数（33．8）与假照组（41．7）无明显差异（P＞0．05），而化疗前预先给予75mGyX射线全身照射组小鼠肺转移瘤结节数（20．3）较单纯化疗组明显减少（P＜0．01）;4次75mGyX射线全身照射组小鼠肺转移瘤结节数（23．5）较假照组明显减少（P＜0．05）;2次75mGyX射线全身照射组小鼠肺转移瘤结节数（39．4）较仅照组有减少趋势，但无统计学意义（P＞0．05）；预先给予75mGyX射线全身照射组小鼠的腹腔Mφ吞噬功能和脾脏NK细胞的细胞毒效应较单纯化疗组明显提高（P＜0．01）。结论：低剂量全身照射可增强（MMC）对Lewis肺癌肺转移的抑制作用及荷瘤小鼠免疫功能，多次低剂量?

Influence of low dose radiation on the pulmonary metastasis of Lewis lung carcinoma in mice

Objective:This paper investigated the influence of whole they irradiation (WBI) withlow dose radiation (LDR) on the pulmonary metastasis of implantable tumor. Methods: The experiment was Perfomed by the use of C57BL/6J mice bearing Lewis lung carcinorna as an experimental ani model. Ten d after tumor implantation, the tumor-bearing mice were given treatments as follows①sham-irradiated control;②2 times 75 mGy X-rays WBI at 3 d intervals,③ 4 times 75 mGy X-raysWBI at 3 d intervals; ④single 3. 0 mg/kg MMCI. P. administration alonel； ⑤preexposure with 75mGy X-rays WBI 6 h before 3. 0 mg/kg MMC chemotherapy, 12 h after chemotherapy,some of themice in groups①， ② and ③ were decapitated to detect the phagocytosic function of Peritonalmacrophage (Mφ）and the cytotoxic activity of natural killer cells (NK) in sPleen twenty-one d aftertumor implantation,all the mice were sacrificed to count the number of lung metastatic fool. Results:MMC chemotherapy alone could not sighficantly reduce the number of lung metastatic foci (sham-(sham-ir-radiated control: 41. 7, MMC chemotherapy alone: 33. 8 P > 0. 05), while the number of lungmetaststis foci in the group that was preexposed 75 mGy X-rays WBI (20. 3) was much fewerthan that in the group with MMC chemotherapy alone (P<0. 05). The number of lung metastatic fool in mice treated with 4 times 75 mGy X-rays WBI (23. 5) was much fewer than that of sham-irradi-ated control (P<0. 01),while the number of lung metatatic fool in mice treated with 2 times 75 mGyWBI (39. 4) had a tendency of reduction,having no statistical significance (P>0. 05). The results ofthe detection of immunological parmeters demonstrated that MMC chemotherapy decreased the levelof MФ and NK cell function while preexposure with 75 mGy X-rays WBI could partly antagonize theimmune suppression of MMC chemotherapy (P