ELF magnetic field affects proliferation of SPD8/V79 Chinese hamster cellsbut does not interact with intrachromosomal recombination

Extremely low-frequency (ELF) magnetic fields have previously been shown to affect conformation of chromatin, cell proliferation, and calcium metaboli sm. Possible mutagenic and carcinogenic effects of ELF have also been discu ssed and tested. In this study, intrachromosomal recombination in the hprt gene after exposure to ELF magnetic field was investigated using the SPD8 r ecombination assay. SPD8 cells, derived from V79 Chinese hamster cells were exposed to ELF at a specific combination of static and ELF magnetic fields , that has been proven to have effects on chromatin conformation in several cell types. The genotoxic agent camptothecin (CPT) was used either as a po sitive control or simultaneously with ELF We also analysed the effect of EL F and CPT on chromatin conformation with the anomalous viscosity time depen dence (AVTD) technique, cell growth kinetics, and cell survival with clonog enic assay. DNA fragmentation was analysed by pulsed field gel electrophore sis (PFGE), ELF did not induce recombination alone, neither did ELF modify the recombinogenic effect of CPT. Although, there was no effect on cell sur vival in response to ELF exposure, inhibition of cell growth was observed. On the other hand, ELF exposure partly counteracted the growth inhibition s een with CPT. The data suggest that ELF exposure may stimulate or inhibit c ell growth depending on the state of the cells. Although, ELF did not induc e recombination, a weak but statistically significant DNA fragmentation com parable with CPT-induced fragmentation was observed with PFGE 48 h after ex posure to ELF. (C) 2001 Elsevier Science B.V. All rights reserved.