Hashimoto S
Department of Radiology, Hokkaido University School of Medicine.
Nihon Igaku Hoshasen Gakkai Zasshi. 1997 Jun;57(7):418-24.
To investigate the anti-tumor effects of low-dose total body irradiation (TBI) histologically, 5 x 10(5) KDH-8 cells were implanted into the right legs of WKAH rats. According to the treatment policies, rats were divided into four groups: non-treated, TBI alone, local irradiation (LI) following TBI, and LI alone. The total dose of TBI was 0.2 Gy, that of LI 10 Gy or 0.2 Gy. Local irradiation of 0.2 Gy had no suppressive effect on the growth of implanted tumor and/or metastasis. In the 10 Gy LI group, growth of the implanted tumor was totally suppressed, and histological findings (H-E staining) showed that there were few viable cells, few tissue-infiltrating cells, and severe fibrotic changes in the tumor tissue. In the TBI group, tumor growth was suppressed during only 7 days after TBI. However, abundant tumor infiltrating cells appeared 24 hours after TBI. Total body irradiation did not enhance the suppressive effect of LI on tumor growth. Metastases of the lung and abdominal lymph nodes were significantly suppressed by TBI. In the TBI group, using the lung-shield with 5 cm lead block, the suppression of lung metastasis was the same as that in the non-shield TBI group. These results suggested that a low dose of TBI brings about anti-tumor effects through a host immune response, unlike those produced by high-dose irradiation.
为了从组织学角度研究低剂量全身照射（TBI）的抗肿瘤作用，将5×10⁵个KDH-8细胞植入WKAH大鼠的右腿。根据治疗方案，大鼠被分为四组：未治疗组、单纯TBI组、TBI后局部照射（LI）组和单纯LI组。TBI的总剂量为0.2 Gy，LI的总剂量为10 Gy或0.2 Gy。0.2 Gy的局部照射对植入肿瘤的生长和/或转移没有抑制作用。在10 Gy LI组中，植入肿瘤的生长被完全抑制，组织学检查结果（苏木精-伊红染色）显示肿瘤组织中存活细胞很少、组织浸润细胞很少且有严重的纤维化改变。在TBI组中，肿瘤生长仅在TBI后7天内受到抑制。然而，TBI后24小时出现了大量肿瘤浸润细胞。全身照射并没有增强LI对肿瘤生长的抑制作用。TBI显著抑制了肺和腹部淋巴结的转移。在TBI组中，使用5 cm铅块的肺屏蔽，肺转移的抑制情况与无屏蔽TBI组相同。这些结果表明，低剂量的TBI通过宿主免疫反应产生抗肿瘤作用，这与高剂量照射产生的作用不同。
