Auteurs

Sannino, A.; Di Costanzo, G.; Brescia, F.; Sarti, M.; Zeni, O.; Juutilainen, J., and Scarfi, M. R. Human fibroblasts and 900 MHz radiofrequency radiation: evaluation of DNA damage after exposure and co-exposure to 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5h)-furanone (MX). Radiat Res. 2009 Jun; 171(6):743-51.

Background
Though most studies confirmed that RF radiation is not directly genotoxic, it is possible that it can enhance the effect of known mutagens. Data on genotoxic effects from combined exposures to RF radiation and other agents are limited and inconsistent. 3-Chloro-4(dichloromethyl)-5hydroxy-2(5H)-furanone (MX), a widespread environmental mutagen and carcinogen, is suitable for studies on possible co-carcinogenic and co-mutagenic effects of RF radiation. Turner’s syndrome (TS) is associated with a chromosomal imbalance; cells from TS subjects could be used to increase the sensitivity of experiments to detect any effect of weakly genotoxic agents. Fibroblasts have been suggested to be more sensitive to RF exposure than other cell types.

Objective
The aim of this study was to investigate whether or not exposure to RF radiation can induce DNA damage in human fibroblasts directly or indirectly as a co-genotoxic agent.

Methods
Cultures of human dermal fibroblasts from a healthy donor (HD) and from the skin of a 16-week fetus with TS were exposed to 900 MHz RF radiation for 24 hours at SAR of 1 W/kg. In additional experiments, TS cell cultures were exposed to RF for 1 hour. In the combined exposure experiments, MX was administered at a concentration of 25 mM for 1 hour immediately after the RF exposure. The cytokinesis-block micronuclei (MN) assay (only in experiments with RF exposure alone) and the alkaline comet assay were used to assess genotoxicity.

Results
No effect of RF radiation on MN frequency was observed either in HD cells or in TS cells. The alkaline comet assay confirmed the lack of effect from RF exposure alone in both HD and TS cells. Exposure to RF radiation did not enhance the effect of MX in HD fibroblasts or TS fibroblasts exposed to RF for 1 hour. In the TS cells exposed to RF for 24 hours and to MX all comet assay parameters were higher (non-significantly) than in the cultures exposed to MX only.

Interpretation
Similar to previous findings in human lymphocytes in vitro and in vivo, the results of this study indicate an absence of genotoxic effects of RF radiation in human fibroblasts. Thus, the hypothesis of higher sensitivity of human fibroblasts to RF radiation was not confirmed. Higher comet assay parameters in the MX+RF exposed cultures than in the MX only exposed cultures in 24-hour experiments with TS fibroblasts were not significant and small compared to the random variations.

Conclusion
Despite the attempts to maximize the probability of detecting an effect, no RF-induced genotoxicity was observed in this study.

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