Radiation and Environmental Biophysics

, Volume 37, Issue 4, pp 267–275

Influence of in vitro low-level gamma-radiation on the UV-induced DNA repair capacity of human lymphocytes – analysed by unscheduled DNA synthesis (UDS) and comet assay

  • M. N. Mohankumar
  • Solomon F. D. Paul
  • P. Venkatachalam
  • R. K. Jeevanram
ORIGINAL PAPER

DOI: 10.1007/s004110050128

Cite this article as:
Mohankumar, M., Paul, S., Venkatachalam, P. et al. Radiat Environ Biophys (1998) 37: 267. doi:10.1007/s004110050128

Abstract

Unscheduled DNA synthesis (UDS) induced by ultraviolet radiation (UV) was studied in human lymphocytes after exposing blood samples in vitro to doses ranging between 1 and 10 mGy gamma-radiation, by way of measuring tritiated thymidine (3H-TdR) uptake in the DNA of these lymphocytes. The results indicate that samples pre-exposed to gamma-ray doses ranging between 2.5 and 4 mGy show higher UDS levels compared with those pre-exposed to doses of less than 2.5 or more than 4 mGy. These results were verified by studying the rate of removal of UV-induced photoproducts using the comet assay. The reason for the increase in DNA repair capacity in this dose range is discussed in comparison with earlier reports on this phenomenon. The DNA repair capacity with respect to inter-individual variability and age is also analysed. The study implies that the comet assay is a simple and sensitive visual method to track nucleotide excision repair and hence can be used to estimate UV-induced DNA repair in the place of the more reliable yet cumbersome and time-consuming, grain-counting autoradiographic technique.

Copyright information

© Springer-Verlag Berlin Heidelberg 1998

Authors and Affiliations

  • M. N. Mohankumar
    • 1
  • Solomon F. D. Paul
    • 1
  • P. Venkatachalam
    • 1
  • R. K. Jeevanram
    • 1
  1. 1.Safety Research and Health Physics Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamilnadu, India Fax: +91-4114-40235, e-mail: nmk@igcar.ernet.inIN