Power frequency magnetic field exposure and gap junctional communication in Clone 9 cells

Exposure to a power-frequency magnetic field has been reported to produce a statistically significant inhibition of gap junctional communication (GJC) in Clone 9 cells that have been pre-stressed by treatment with low concent rations of chloral hydrate (CH) [C.F. Blackman, J.P. Blanchard, S.G. Benane , D.E. House, J.A. Elder, Double blind test of magnetic field effects on ne urite outgrowth, Bioelectromagnetics, 19 (1998) 204-209]. This observation might provide mechanistic insight into the possible role of electromagnetic fields (EMFs) in the carcinogenic process, since cancer cells frequently s how decreased or absent GJC, and tumor promoting chemicals have been observ ed to inhibit GJC. Magnetic field exposure conditions were 45 Hz, 23.8 muT rms + parallel DC 36.6 muT, for 30 min of exposure. The responses of Clone 9 cells to the GJC-inhibiting effects of the tumor promoter 12-O-tetradecan oylphorbol 13-acetate and the chemical CH were evaluated and compared to re ported results [S.G. Benane, C.F. Blackman, D.E. House, Effects of perchlor oethylene and its metabolites on intercellular communication in Clone 9 rat liver cells, J. Toxicol. Environ. Health, 48 (1996) 427-437]. Before magne tic field exposure, cells were exposed fur 24 h to either 3 (nine experimen ts) or 5 mM (11 experiments) CH to produce GJC of 67% or 50%, respectively, relative to unexposed controls. GJC was assessed microscopically using the scrape-loading technique and a blinded protocol. No statistically signific ant effect was observed due to magnetic field exposure with either CH conce ntration. Published by Elsevier Science S.A.