A Reform Measure of Radiotherapy for Lung Cancer by Protecting the Lung against Radiation Damage.

用X射线局部照射8周龄雌性C3H小鼠的胸廓。11Gy以下照射组小鼠的存活率在照射后300d开始下降，随后缓慢下降。另一方面，大多数小鼠直到暴露后120天才死亡，当时它们受到超过15Gy射线的照射。这些结果表明，11-13Gy射线照射的死亡机制是不同的。照射组和未照射组在检测体重时，前者的体重停止增加，表现为生长迟缓，即使给予小剂量照射，存活率也没有下降。测定受照小鼠体重是检测辐射损伤的一种较好的检测方法，测定了WR-2721、弹力酶和地塞米松对辐射损伤的防护作用。其中以WR-2721效果最好。接受15Gy射线照射的小鼠在照射后120天内死亡，而接受15GyAn…照射的小鼠的存活率在照射后400天，More d WR-2721与未照射对照组几乎相似。比较各剂量组的体重，WR-2721剂量组的体重均小于未照射对照组，表现为生长迟缓。这一结果也支持体重的测定比存活率更敏感地检查辐射损伤。弹性蛋白酶联合13Gy时可提高受照小鼠的存活率，而联合15Gy时则不起作用。弹性蛋白酶可能只能保护小鼠免受轻微的辐射损伤。地塞米松即使在照射前和照射后3个月给药，也能有效地保护小鼠免受辐射损伤。这一结果为临床应用提供了很好的信息。按照Seyer等人的方法，用胃酶和醋酸从小鼠肺中提取胶原。该方法适用于小鼠肺组织，SDS-PAGE分析显示典型的I型胶原蛋白斑块。我们计划分析经保护性药物治疗和照射后多次切除的小鼠的胶原亚型。肺癌患者在照射前和照射后取肺灌洗液和血清，测定其中&lt；III&gt；型前胶原N端肽的水平。照射后灌洗液中的多肽水平显著升高，尤其是胸部X线片显示放射性纤维化的患者。较少

The thoraxes of 8 week-old female C3H mice wee locally irradiated by X-ray. The survival rates of mice which were given under 11Gy began to decrease 300 days after irradiation and made a slow descent. On the other hand, most mice died until 120 days after exposure when they were exposed to over 15Gy. These results suggest that the mechanisms of death were different between 11-13Gy. When the body weight was checked in both irradiated and non-irradiated groups, those of the former stopped to increase and showed growth retardation, even if a small dose of irradiation was given and the survival rates did not decrease. The determination of body weight in irradiated groups was a good assay method to check the radiation damage.The protective effects of WR-2721, Elastase and Dexamethasone against radiation damage was determined. WR-2721 was most effective in these. The mice which were given 15Gy died within 120 days after irradiation, however, the survival rate of mice which were given 15Gy an … More d WR-2721 was almost similar as non-irradiated controls at 400 days after irradiation. When body weights of these groups were compared, those of the WR-2721 group were smaller than the non-irradiated control and showed growth retardation. This result also supports that the determination of body weight is more sensitive than the survivla rate to check the radiation damage. Elastase could improve the sirvival rate of irradiated mice when it was combined with 13Gy but it did not work when combined with 15Gy. Elastase might be albe to protect the mice only against the mild radiation damage. Dexamethasone was effective to protect mice against radiation damage even if the drug was given before and 3 months after irradiation. This result is a good information for clinical applications.The collagen was extracted from the mouse lung with pepsin and acetic acid according to the method by Seyer et al. This method could be available to the mouse lung and the SDS-PAGE analysis showed typical collagen type I petterns. We plan to analyse the collagen subtypes in mice which were treated protective drugs and sacrified several times after irradiation.The lung lavages and sera from the lung cancer patients were taken before and after irradiation to determine the levels of type <III> procollagen N-terminal peptide in them. The peptide levels in lavage significantly increased after irradiation, especially in patients whose chest X-rays showed radiation fibrosis. Less