Coupling of oxidative stress responses to tricarboxylic acid cycle and prostaglandin E<sub>2</sub> alterations in <i>Caenorhabditis elegans</i> under extremely low-frequency electromagnetic field

<p><b>Purpose:</b> With all-pervasive presence of extremely low-frequency electromagnetic field (ELF-EMF) in modern life, ELF-EMF has been regarded as an essential factor which may induce changes in many organisms. The objective of the present study was to investigate the physiological responses of <i>Caenorhabditis elegans</i> (<i>C. elegans</i>) to 50 Hz, 3 mT ELF-EMF exposure.</p> <p><b>Materials and methods:</b> Worms were exposed to ELF-EMF from the egg stage until reaching the fourth larva (L4) stage. After exposure, expressions of the tricarboxylic acid (TCA) cycle enzymes were examined by qRT-PCR and western blot analysis. Two lipid metabolites were detected by GC-MS. Reactive oxygen species (ROS) level was detected by dichlorofluorescein staining and worm antioxidant system was investigated by enzymatic activity analysis, including detection of the superoxide dismutase and catalase (CAT) activity and the total antioxidant capacity (T-AOC).</p> <p><b>Results:</b> The TCA cycle enzyme, fumarase was found with decreased expression under ELF-EMF exposure. And arachidonic acid (ArA) and prostaglandin E<sub>2</sub>(PGE<sub>2</sub>) showed elevated concentrations, with increased expression of prostaglandin E<sub>2</sub> synthase (PGES-2) in ELF-EMF exposed worms. Significant elevation of ROS level was identified accompanied with the significant depression of T-AOC in response to ELF-EMF.</p> <p><b>Conclusions:</b> Our results suggested that exposure to 50 Hz, 3 mT ELF-EMF in <i>C. elegans</i> can elicit disruptions of the TCA cycle metabolism and PGE<sub>2</sub> formation, coupling ELF-EMF-induced oxidative stress responses. Our study probably will attract increasing attentions to the controllable application of ELF-EMF associated with health and disease.</p>