The Protective Effect of Static Magnetic Fields with Different Magnetic Inductions against Fluoride Toxicity Is Related to the NRF2 Signaling Pathway

Abstract

A redox imbalance disrupts the cellcycle and the proliferation process, and contributes to the initiation of programmed cell death. One of the pathways that are important for redox homeostasis is the Nrf2-ARE signaling pathway. Fluoride as well as static magnetic fields (SMF) are associated with the concepts of oxidative stress, and thus programmed cell death. Therefore, this study aimed to assess the connection between oxidative stress and apoptosis in human cells co-exposed to fluoride and a SMF with a different magnetic induction and to determine whether the Nrf2-signaling pathway is involved in these effects. The research was realized using normal human dermal fibroblasts that had been co-exposed to fluoride (0.3 mmol/L) and a SMF with a different magnetic induction (0.45 T, 0.55 T, 0.65 T) for 12 h. The mRNA levels of the cellular antioxidant system-related genes and apoptosis-related genes were assessed using the quantitative reverse transcription polymerase chain reaction (RT-qPCR) method. Our results indicated that the increased activity of antioxidant enzymes (SOD1 (superoxide dismutase 1), SOD2 and GSR (glutathione reductase)) suggests the restoration of the cell redox homeostasis that had been disturbed by fluoride, and also that the genes whose expression is associated with the induction of apoptosis are down regulated as a result of exposure to a SMF. The SMF with a 0.65 T flux density had the strongest effect on the fibroblasts. Moreover, our findings demonstrated that the Nrf2 transcription factor plays a crucial role in the protective effect of a SMF against fluoride toxicity in human cells. The results of these studies can form the basis for developing therapeutic strategies for apoptosis and oxidative stress-related diseases.