Magnetic fields modulate metabolism and gut microbiome in correlation withPgc-1αexpression: Follow-up to an in vitro magnetic mitohormetic study

Exercise modulates metabolism and the gut microbiome. Brief exposure to low mT-range pulsing electromagnetic fields (PEMFs) was previously shown to accentuate in vitro myogenesis and mitochondriogenesis by activating a calcium-mitochondrial axis upstream of PGC-1 alpha transcriptional upregulation, recapitulating a genetic response implicated in exercise-induced metabolic adaptations. We compared the effects of analogous PEMF exposure (1.5 mT, 10 min/week), with and without exercise, on systemic metabolism and gut microbiome in four groups of mice: (a) no intervention; (b) PEMF treatment; (c) exercise; (d) exercise and PEMF treatment. The combination of PEMFs and exercise for 6 weeks enhanced running performance and upregulated muscular and adiposePgc-1 alpha transcript levels, whereas exercise alone was incapable of elevatingPgc-1 alpha levels. The gut microbiomeFirmicutes/Bacteroidetesratio decreased with exercise and PEMF exposure, alone or in combination, which has been associated in published studies with an increase in lean body mass. After 2 months, brief PEMF treatment alone increasedPgc-1 alpha and mitohormetic gene expression and after >4 months PEMF treatment alone enhanced oxidative muscle expression, fatty acid oxidation, and reduced insulin levels. Hence, short-term PEMF treatment was sufficient to instigate PGC-1 alpha-associated transcriptional cascades governing systemic mitohormetic adaptations, whereas longer-term PEMF treatment was capable of inducing related metabolic adaptations independently of exercise.