Studies on the role of moderate doses of ionizing radiation-induced cellular senescence in mouse lung tissue.

Purpose: To investigate the role of moderate doses of ionizing radiation-induced cellular senescence in mouse lung tissue and whole-body inflammation levels.

Material And Methods: Forty-two C57BL/6J mice were randomly divided into the control group, the 1, 3, and 7 days after 2 Gy irradiation group, and the 1, 3, and 7 days after 4 Gy irradiation group, with six mice in each group. The histopathology, cellular senescence, oxidative-antioxidant, DNA damage repair, and inflammation-related indicators of irradiated mice were examined.

Results: Compared with the control group, the histopathological scores, the positive area of senescence-associated-β-galactosidase (SA-β-Gal) staining, and the mRNA levels of senescence-related genes in the lung tissues in all dose groups increased on 1, 3, and 7 days after irradiation. In peripheral blood, erythrocytes, leukocytes, platelets, hemoglobin, 8-hydroxydeoxyguanosine (8-OHdG), C-reactive protein, and other indicators showed a different trend in all dose groups. The levels of malondialdehyde(MDA), superoxide dismutase (SOD), glutathione (GSH), and 8-OHdG in the lung tissue showed different trends after 2 Gy and 4 Gy irradiation. The 8-Oxoguanine DNA glycosylase 1 () and O-6-methylguanine-DNA methyltransferase () mRNA levels showed a trend of increasing and then decreasing. The levels of whole-body inflammation were significantly correlated with the levels of indicators related to cellular senescence and damage repair in the lung tissue of mice.

Conclusions: The moderate doses of ionizing radiation induce oxidative stress, and DNA damage and increase DNA repair gene expression in mouse lung tissue. The lung tissue cellular senescence correlates with the level of whole-body inflammation.