In vitro radiation sensitivity of mouse lung fibroblasts isolated by flow cytometry.
OBJECTIVE
Recently, we have isolated two major fibroblast cells (Thy-1+, Thy-1-) from mouse LAF1 lung tissue using the anti-Thy-1 antibody expression and fluorescence activated cell sorter. To examine the possibility that x- or gamma-ray-induced pulmonary fibrosis at the late stage of injury could arise from radioresistant cell subpopulations, the radiation sensitivities of Thy-1+ and Thy-1- cells were evaluated by the colony forming assay.


METHODS
Cell survival curves, repair of potentially lethal damage (PLD) and sublethal damage (SLD), and cell-age response curves were obtained after Cs-137 gamma-ray irradiation.


RESULTS
The cell survival curves measured after 0-10 Gy gamma-ray showed that Thy-1+ cells were slightly more radioresistant than Thy-1- cells. The D0, n, alpha, and beta values measured from the survival curves also confirmed this observation. After a single dose of 10 Gy, a small amount of PLD repair was observed in Thy-1- cells, while no PLD repair was found in Thy-1+ cells. Although the initial cell survival level of Thy-1- cells was lower, the final survival levels of Thy-1+ and Thy-1- cells became identical at 8 h after irradiation due to the PLD repair. After split-dose irradiation of 4 Gy followed by 4 Gy, a similar extent and rate of SLD repair was found in Thy-1+ and Thy-1- cells. Cell-age response curves were obtained from irradiated G0/G1, S, and G2M cells separated by centrifugal elutriation and irradiated with 8 Gy gamma-ray. The results indicated that Thy-1+ and Thy-1- cells had a similar S resistant, and G1, G2M-sensitive radiation cell-age response curve.


CONCLUSIONS
This study suggests that the selection of radioresistant lung fibroblast may not be responsible for the development of lung fibrosis in irradiated LAF1 mouse.
Keng
P C
PC
Department of Radiation Oncology, University of Rochester Cancer Center, NY 14642.
Phipps
R
R
Penney
D P
DP
D000818:Animals; D002460:Cell Line; D002469:Cell Separation / Q000379:methods; D002470:Cell Survival / Q000528:radiation effects; D005347:Fibroblasts / Q000528:radiation effects; D005434:Flow Cytometry; D008168:Lung / Q000528:radiation effects*; D051379:Mice; D011658:Pulmonary Fibrosis / Q000209:etiology; D011836:Radiation Tolerance; D018800:Thy-1 Antigens / Q000032:analysis
D018800:Thy-1 Antigens