Observation of lung injury and repair during growth and development in rats

1.本文观察了出生前1天至出生后42天大鼠肺组织DNA含量和DNA聚合酶及其α、β型活性的变化。结论是：（1）肺中的细胞增殖在出生后的前两周最为活跃，这是由DNA聚合酶α活性和DNA含量的增加所支持的，以及（2）DNA修复能力、DNA聚合酶β活性在整个出生前和出生后时期保持恒定。本文研究了博莱霉素重复注射后小鼠肺DNA合成和细胞成分的变化。(1)BLM的重复注射导致肺细胞中的DNA损伤;（2）DNA修复功能随后增加，这得到DNA聚合酶-β活性增加的发现的支持;和（3）这些进一步导致细胞增殖，这得到DNA聚合酶-α活性和DNA含量增加的支持。

1. Changes in the DNA content and the activity of DNA polymerase and its alpha and beta forms were studied on the lungs, which were exposured in hyperoxia, of one day prenatal to 42 day postnatal rats. It is concluded that : (1) cellular proliferation in the lung is most active during the first two weeks after birth as supported by increase in both DNA polymerase alpha activity and DNA content, and (2) the capacity for DNA repair, DNA polymerase beta activity throughout the pre and postnatal period remains constant.2. Changes in the DNA synthesis and cellular constituents of mouse lung following repeated bleomycin injections were studied. (1) repeated injections of BLM cause DNA injury in lung cells ; (2) there is a subsequent increase in the DNA repair function as supported by the finding of an increase in DNA polymerase-beta activity ; and (3) these lead further to cell prolifration as supported by the increase in both DNA polymerase-alpha activity and DNA content.