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.
Department of Radiation Oncology, University of Rochester Cancer Center, NY 14642.
P C
PC
Keng
R
R
Phipps
D P
DP
Penney
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