Recovery of murine lens epithelial cells from single and fractionated doses of X rays and neutrons.
Subpopulations of mouse lens epithelial cells, differing in proliferative status, were irradiated with either X rays or fission spectrum neutrons given singly or in four weekly fractions. After various times, epithelia were mitogenically stimulated by wounding and DNA synthesis responses were determined by incorporation of [3H]thymidine. At 1 h following both X and neutron irradiations, significant suppression of the wound response after single doses and a sparing effect of fractionation were evident in both the mitotically quiescent and the slowly proliferating subpopulations. At 1 week following single or fractionated doses of both radiations, recovery was evident in both subpopulations. By 4 weeks, the quiescent subpopulation showed significant recovery after both single and fractionated doses of X rays or neutrons. In contrast, a marked decreased ability to respond after neutron irradiation and, in addition, a significant enhancement effect of neutron fractionation were observed for the slowly proliferating subpopulation. Per gray, neutrons were about 7.5 times more effective than X rays as a single dose and 25 times more effective in four equal fractions. The shift from an initial sparing to a final enhancing effect of neutron fractionation for the slowly proliferating subpopulation has importance for understanding divergent early and late radiation responses following dose fractionation.
Riley
E F
EF
Radiation Research Laboratory, University of Iowa, Iowa City 52242.
Miller
R C
RC
Lindgren
A L
AL
D000818:Animals; D004247:DNA / Q000096:biosynthesis; D004847:Epithelial Cells; D004848:Epithelium / Q000528:radiation effects; D005260:Female; D007908:Lens, Crystalline / Q000528:radiation effects*; D051379:Mice; D008938:Mitosis / Q000528:radiation effects; D009502:Neutrons; D011829:Radiation Dosage; D014965:X-Rays
D004247:DNA