A simple technique for quantitation of low levels of DNA damage in individual cells☆
Abstract
Human lymphocytes were either exposed to X-irradiation (25 to 200 rads) or treated with H2O2 (9.1 to 291 μM) at 4 °C and the extent of DNA migration was measured using a single-cell microgel electrophoresis technique under alkaline conditions. Both agents induced a significant increase in DNA migration, beginning at the lowest dose evaluated. Migration patterns were relatively homogeneous among cells exposed to X-rays but heterogeneous among cells treated with H2O2. An analysis of repair kinetics following exposure to 200 rads X-rays was conducted with lymphocytes obtained from three individuals. The bulk of the DNA repair occurred within the first 15 min, while all of the repair was essentially complete by 120 min after exposure. However, some cells demonstrated no repair during this incubation period while other cells demonstrated DNA migration patterns indicative of more damage than that induced by the initial irradiation with X-rays. This technique appears to be sensitive and useful for detecting damage and repair in single cells.
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This research was supported by the National Institute on Aging.
- 1
N.P.S. was supported by the Glenn Foundation for Biomedical Research and by the Donald H. and Charity Yarborough Fund.
- 2
M.M. is supported by the John D. and Catherine T. MacArthur Foundation Research Program on Successful Aging.
- 3
R.R.T. is supported at Brookhaven National Laboratory by the Department of Energy under prime contract DE-AC02-76CH00016.