A primary study on rat fetal development and brain-derived neurotrophic factor levels under the control of electromagnetic fields.

Brain-derived neurotrophic factor (BDNF) is a growth factor that plays a crucial role in forming synaptic connections and repairing nerve cells. BDNF also promotes the growth and differentiation of these cells. Furthermore, functional mutations in the BDNF receptor have been associated with conditions such as depression and obesity. Previous studies have demonstrated a direct link between fetal growth and brain health. According to these studies, BDNF modulates patterns of fetal development, particularly with regard to weight. This study measured the body dimensions and BDNF concentrations of offspring from pregnant rats to determine the effect of Wi-Fi exposure on their growth.

Twenty pregnant albino Wistar rats were randomly assigned to either the Wi-Fi group or the control group. After birth, 12 male fetuses were randomly selected from each group. The pregnant rats were housed in separate temperature-controlled rooms: an unshielded room for the Wi-Fi group and a room shielded with aluminum foil for the control group. A commercially available 2.4 GHz Wi-Fi modem was placed on a table 1 m away from the cages of the Wi-Fi group. The pregnant rats were exposed to Wi-Fi radiation for 6 hours daily for approximately 20 days (throughout the entire gestation period). Body length, tail length, and body weight were measured at birth and on the 21st and 56th postnatal days. An ELISA kit was used to measure BDNF levels toward the end of the experiment.

On day 56 after birth, the body weight of newborn rats exposed to electromagnetic fields (Wi-Fi) was approximately 10% lower (approx. 207 g) than that of the control group (approx. 230 g). However, this difference was not statistically significant. In contrast, the body length of the Wi-Fi group at birth was significantly greater than that of the control group: 51.0 mm versus 45.6 mm. The Wi-Fi group's tail length at birth (20.0 mm) was also significantly longer than the control group's (17.2 mm). However, by the 21st day after birth, the control group's tail length was significantly longer (by approx. 45%) than that of the Wi-Fi group: 67.3 mm versus 46.3 mm. By day 56, the control group's tail length had increased by 14%, reaching 156.2 mm, while the Wi-Fi group's remained at 136.5 mm. Fifty-six days after birth, the concentrations of brain-derived neurotrophic factor (BDNF) were statistically significantly lower in the Wi-Fi group (6.8 ± 0.2 ng/mL) than in the control group (7.08 ± 0.16 ng/mL), representing only a 4% reduction.

This study was limited by the small sample size, the lack of growth hormone level measurements, the short exposure duration (6 hours per day for 20 days), and the lack of BDNF measurements at birth.

Editor’s note:

Leptin and BDNF interact through complex signaling pathways that regulate energy homeostasis, mood, and neurological development. In the adult brain, leptin acts as a potent regulator of BDNF expression, particularly in the hippocampus. In rodents, an increase in leptin occurs after birth (which can compensate for reduced in utero BDNF levels). However, this increase does not occur in humans. Overall, leptin and BDNF form a critical adipose tissue–brain axis. In adults, leptin signaling modulates BDNF expression. In fetuses, however, maternal levels of both factors contribute to the programming of metabolic and neural development. The findings following Wi-Fi exposure (at an estimated low, non-thermal power density of 10 mW/m²) are interesting. At the very least, the differences in body length suggest significant and problematic disruption of the normal growth process. However, it is unclear to what extent this is due to BDNF levels because they were only measured on day 56 (when the rats were sacrificed). At that time, there was only a 4% reduction in BDNF levels measured in the Wi-Fi group, which is likely an irrelevant amount. This study should be repeated/replicated with a larger number of experimental animals and additional hormone measurements, such as leptin and growth hormone levels. BDNF levels should also be determined at birth and on day 21. In addition, BDNF levels in pregnant females should be measured because BDNF in the mother’s blood reaches the developing fetuses via the placenta. Therefore, it is not yet clear at what level (mother or fetus) Wi-Fi can affect BDNF levels. (AT)