To evaluate the potential of these microwaves to induce DNA-DNA or DNA-protein crosslinks, microwave-exposed cells were treated with 4 Gy of gamma radiation and the DNA migration pattern in the comet assay was evaluated. The presence of DNA-DNA or DNA-protein crosslinks in cells containing DNA damage has been shown to reduce the level of DNA migration found in the comet assay.
|Exposure duration||continuous for 2 h|
|Chamber||Chamber with up to 10 radial transmission lines (RTLs), consisting of parallel-plates with aluminium bottom plate and a metal-faced composite top plate [Moros et al., 1999].|
|Setup||The electric field of the waves propagating radially outward was perpendicular to the cell layer. The tangential magnetic field was perpendicular to the EF and the propagation direction.|
|Sham exposure||A sham exposure was conducted.|
Ionizing gamma radiation (4 Gy) induced significant DNA damage. However, no DNA damage could be revealed after exposure to 2450 MHz CW (continuous wave) microwaves alone. The crosslinking agent CDDP (cis-diamine dichloroplatinum II (cisplatin), used as a positive control) significantly reduced both the comet length and the normalized comet moment in the cells irradiated with 4 Gy gamma rays. In contrast, 2450 MHz microwaves did not impede the DNA migration induced by gamma radiation. When control cells were treated with proteinase K, both parameters increased in the absence of any DNA damage. However, no additional effect of proteinase K was seen in samples exposed to the microwaves or in samples treated with the combination of microwaves and radiation. On the other hand, proteinase K treatment was ineffective in restoring any migration of the DNA in cells pretreated with CDDP and exposed to gamma rays. When DNA-protein crosslinks were specifically measured, the authors found no evidence for the induction of DNA-protein crosslinks or changes in amount of the protein.
Thus, the results show that a 2-h exposure to 1.9 W/ kg of 2450 MHz CW microwaves did not induce measurable alkali-labile DNA damage or DNA-DNA or DNA-protein crosslinks.