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

用X线局部照射8周龄雌性C_3H小鼠胸部。11 Gy以下剂量组小鼠的存活率在照射后300天开始下降，并缓慢下降。另一方面，大多数小鼠在暴露后120天死亡，当它们暴露于15 Gy以上时。提示11- 13 Gy剂量组的死亡机制不同。无论是照射组还是非照射组，体重均停止增长，表现为生长迟缓，即使给予小剂量照射，存活率也不降低。测定辐射组的体重是一种较好的检测辐射损伤的方法，并测定了WR-2721、弹性蛋白酶和地塞米松对辐射损伤的保护作用。WR-2721在这些方面最有效。15 Gy组小鼠在照射后120天内死亡，而15 Gy组小鼠的存活率明显低于对照组， ...更多信息 d WR-2721在照射后400天几乎与未照射的对照相似。当比较这些组的体重时，WR-2721组的体重小于未照射对照组，并且显示出生长迟缓。这一结果也支持了测定体重比存活率更能灵敏地检测辐射损伤。弹性蛋白酶与13 Gy联合应用能提高受照小鼠的存活率，与15 Gy联合应用则无明显作用。弹性蛋白酶可能只能保护小鼠免受轻度辐射损伤。即使在照射前和照射后3个月给予地塞米松，也能有效保护小鼠免受辐射损伤。本实验采用Seyer等提出的方法，用胃蛋白酶和醋酸从小鼠肺组织中提取胶原蛋白，经SDS-PAGE分析，得到了典型的Ⅰ型胶原蛋白条带。本研究拟对经保护性药物治疗及多次照射后再照射的小鼠进行胶原亚型分析，并对肺癌患者在照射前后分别取肺灌洗液及血清，测定其型<III>前胶原N端肽的含量。灌洗液中的肽水平在照射后显著升高，特别是在胸部X线显示放射性纤维化的患者中。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