Investigating the effect of radiofrequency electromagnetic field exposure on molecular pathways related to insulin resistance and adipogenesis in zebrafish embryos - A pilot study without quantitative exposure metrics

In recent years, obesity has become a global problem in children and adolescents, in parallel with the rapid increase in the use of information and communication technology. Recognizing the embryonic causes of obesity may help prevent adverse adult health outcomes. In our study, we hypothesized that radiofrequency-electromagnetic field (RF-EMF) exposure during embryogenesis would affect the molecular mechanisms related to adipogenesis and insulin resistance in zebrafish. To achieve this, we set up a system that emits RF-EMF in the 900 MHz band and subjected zebrafish embryos to its RF-EMF. We created two groups in which we exposed 30 min (EMF-30) and 60 min (EMF-60) per day, and a control group that was not exposed to RF-EMF. We ended the exposure at 96 hpf and analyzed the expression of lepa, ins, and pparg that are involved in the regulation of glucose and lipid metabolism. In addition, we analyzed oxidative stress parameters, embryonic development, and locomotor activity. We found decreased mRNA transcript abundance of lepa, ins, pparg, and activities of superoxide dismutase and acetylcholine esterase, along with increased lipid peroxidation (LPO), nitric oxide (NO), and glutathione S-transferase (GST). Locomotor activity increased in the EMF-30 group and decreased in the EMF-60 group. Our results showed that exposure to RF-EMF during the embryonic period disrupted the molecular pathways related to insulin resistance and adipogenesis in zebrafish. However, due to limited available resources, we were not able to appropriately quantify the actual RF exposure strength of the samples. Hence the results reported here should only be seen as preliminary, and further studies employing high quality exposure apparatus and dosimetry should be carried out in future.