Effect of GSH depletion, hyperthermia, and pulsed magnetic fields on an Hsp70/Luc reporter system

Heat shock proteins, particularly Hsp70, are produced in response to a number of cellular stresses. The most well known example is exposure to heat, but conditions of oxidative stress have also been shown to induce HSP70 [1; 2; 3] . GSH is one of the most important low molecular weight antioxidants in the cell. Depletion of GSH is known to increase the amount of reactive oxygen species (ROS) in a cell thus exposing the cell to oxidative stress [4]. A number of groups have found that modulating the concentration of GSH in the cell alters the Hsp70 protein levels [5; 6; 7; 8]. It has also been shown, in some circumstances, that exposure to a magnetic field alters levels of HSP70 [9]. However, this effect has not been consistently reproduced. More consistency has been achieved when a magnetic field was combined with a primary stress such as heat exposure. The aim of this study was to analyze the amount of bioluminescence produced by a Hsp70/luciferase reporter system to evaluate the possibility of a synergistic effect of exposure to pulsed magnetic fields (PMF) with frequencies ranging from 0.05 Hz to 50 Hz following A) cellular GSH depletion, B) exposure to heat or C) a combination of GHS depletion and heat.