Effect of Radiation on Cultured Human Normal Keratinocytes and Melanocytes

Yoo, Han Dong; Kim, Nack In; Park, Jai Kyung; Hong, Seong Eon; Haw, Choong Rim

Abstract

BACKGROUND: Radiation has been used in t,he medical field of dragnosis and treatment. There is widely used ionizing radiat:ion such as naturally occuring r-rays or machine-made X-ray. This radiation is able to induce the structural and functional alterations of the mammalian cells. But we have few detailed reports on the effects of radiation on epidermal cells and their immune functions.
OBJECTIVE
This study was performed to investigate the effect of radiation on cultured human keratinocytes and melanocytes.
MATERIALS AND METHODS
Cultured human keratinocytes and melanocytes were irradiated with 2,6, l0Gy from a Co saurce and stimulated by 100 U/ml of ekratinocyte immediately after irradiation. We investigated cell numbers and morphological changes, DNA synthesis and HLA-DR antigen expression.
RESULTS
After exposure to r-ray, the proliferation of keratinocytes and melanocytes decreased in a time and dose dependent fashion to each control group. Tliey showed decreased density, a larger size and a round appearance after radiation exposure and an especially shortened and decreased number of dendrites in the melanocytes. In DNA synthesis counted using [H]-thymidine incorporation, the keratinocvtes decreased values in a dose depen(lent manner at 24 and 72 hours after irradiation but no differense was observed at 168 hours. In melanocytes, there was a greater decrease than that of keratinocytes. The melanin content/cell in all radiation exposed groups increased in a time and dose dependent fashion t,o each contr ol group. HLA-DR antigen expression on keratinocytes after radiat,ion exposure decreased to the control group, but there were no significant differences acccirding to the dose of radiation, And there were no significant diifferences of HLA-DR antigen expression on the melanocytes betweer. controls and the radiation exposed groups.
CONCLUSION
Antiproliferative activity was dependent on the exposure time and dose of r-ray exposure. According to the time after radiation exposure, melanogenic activity was stimulated. The expression of HLA-DR, antigen decreased in keratinocyte after radiation exposure but there was no decrease in melanocytes.