Prenatal exposure to iPhone radiation reduces cerebellum & impairs social behavior in chicks
Since it is unethical to experiment on humans, numerous studies have been conducted on fetal development using animal models. Recently, fifteen peer-reviewed, experimental studies have found that prenatal exposure to wireless radiation produces the following adverse health effects on offspring in the following species.
Social behavioral testing and brain magnetic resonance imaging in chicks exposed to mobile phone radiation during development
Zhou Z, Shan J, Zu J, Chen Z, Ma W, Li L, Xu J. Social behavioral testing and brain magnetic resonance imaging in chicks exposed to mobile phone radiation during development. BMC Neurosci. 2016 Jun 10;17(1):36. doi: 10.1186/s12868-016-0266-7.
BACKGROUND: The potential adverse effect of mobile phone radiation is currently an area of great concern in the field of public health. In the present study, we aimed to investigate the effect of mobile phone radiation (900 MHz radiofrequency) during hatching on postnatal social behaviors in chicks, as well as the effect on brain size and structural maturity estimated using 3.0 T magnetic resonance imaging. At day 4 of incubation, 76 normally developing chick embryos were divided into the control group (n = 39) and the radiation group (n = 37). Eggs in the radiation group were exposed to mobile phone radiation for 10 h each day from day 4 to 19 of incubation. Behavioral tests were performed 4 days after hatching. T2-weighted MR imaging and diffusion tensor imaging (DTI) were subsequently performed. The size of different brain subdivisions (telencephalon, optic lobe, brain stem, and cerebellum) and corresponding DTI parameters were measured. The Chi-square test and the student's t test were used for statistical analysis. P < 0.05 was considered statistically significant.
RESULTS: Compared with controls, chicks in the radiation group showed significantly slower aggregation responses (14.87 ± 10.06 vs. 7.48 ± 4.31 s, respectively; P < 0.05), lower belongingness (23.71 ± 8.72 vs. 11.45 ± 6.53 s, respectively; P < 0.05), and weaker vocalization (53.23 ± 8.60 vs. 60.01 ± 10.45 dB/30 s, respectively; P < 0.05). No significant differences were found between the radiation and control group for brain size and structural maturity, except for cerebellum size, which was significantly smaller in the radiation group (28.40 ± 1.95 vs. 29.95 ± 1.41 cm(2), P < 0.05). The hatching and heteroplasia rates were also calculated and no significant difference was found between the two groups.
CONCLUSIONS: Mobile phone radiation exposure during chick embryogenesis impaired social behaviors after hatching and possibly induced cerebellar retardation. This indicates potential adverse effects of mobile phone radiation on brain development.
Global system for mobile communication (GSM) is widely used in mobile phones and its electromagnetic waves range in frequency from 300 MHz to 3 GHz. The electromagnetic field (EMF) produced by these electromagnetic waves could lead to various pathological changes in viable tissues and cells via heat-related and non-heat-related effects, such as oxidative stress, Ca2+-signal channel’s adjustment, and DNA damage[8–11].
Many pregnant women wear so-called radiation-proof clothes to avoid potential influence of EMF on the fetus. One epidemiological research study showed that exposure to mobile phones prenatally and postnatally is associated with emotional problems and hyperactivity in children at approximately the age of school entry . However, another epidemiological study suggests that maternal mobile phone use during pregnancy does not increase the risk of behavioral problems in children . Few clinical studies have been performed because of ethical limitations. Some experiments in small animals such as rats and chicks have been performed to investigate the effect of EMF on brain development, with conflicting results [14–17].
The chick embryo is an accessible and economical model, which has an extensive history of use in developmental biology, transplantation research, pharmaceutical teratogenicity evaluation, and cancer research .
Since the brains of rodent embryos mature quite late and are not completely developed at birth , the chick embryo is a more suitable animal model than the rodent to investigate the effect of exposure to environmental factors during embryogenesis on brain development.
An iPhone 4s (GSM 900 MHz) was used as a source of radiation and placed in the center of the hatching plate. Experimental eggs were placed around the mobile phone as shown in Fig.1. The average intensity of electromagnetic radiation next to the iPhone 4s during 1 min of ringing was 3.03 µW/cm2 .... Embryos in the experimental group were continuously irradiated for 10 hours each day (from ) from day 4 to 19 of incubation. An Android-based custom-made software was used to call the iPhone 4s in the incubator automatically. Each call lasted 1 min with 30 second gaps between calls .... The surface temperature of the experimental eggs was 37–38 °C, which was randomly measured five times a day to exclude possible heating effects of electromagnetic radiation and/or battery charging.
Our present research established that exposure to mobile phone radiation during embryonic development has an adverse effect on chick social behaviors after hatching, reducing aggregation time and belongingness, and resulting in weaker vocalization. Similar animal studies have been carried out in rat offspring, yielding similar results [27, 28]. Here, T2-weighted MRI showed no adverse effect of radiation exposure on the size of different brain subdivisions, except the cerebellum. The cerebellum size in the radiation group was smaller than that in the control group. The cerebellum is associated with motor coordination and balance skills. The retardation of cerebellar development may influence these functions and manifest as an adverse effect on social behaviors. A previous electrophysiological and behavioral study showed that EMF radiation affects the cerebellar function of rat offspring . EMF radiation emitted from mobile phones may cause structural damage to neurons.
The mechanism underlying the effect of electromagnetic radiation on brain growth has not been fully clarified. Attention has widely been paid to the harmful effects of oxidative stress caused by electromagnetic radiation exposure during embryogenesis. Moderate oxidative stress promotes neuronal differentiation and proliferation; however, excessive oxidative stress causes apoptosis and necrosis . The embryo is most sensitive to oxidative stress in the early developmental stage. With the development-related formation of antioxidant defenses, the embryo becomes more resistant to oxidative stress. The balance between moderate oxidative stress and the embryo’s antioxidant defenses is important for neuronal survival. “Reductive stress” caused by antioxidants may be as dangerous to neuronal survival as oxidative stress . In addition, the magnitude of oxidative stress is different in different regions of brain. Electromagnetic radiation may upset the balance between the oxidative and anti-oxidative stress systems in a specific region of the brain during the period of brain growth and thus affect its function.
Center for Family and Community Health
School of Public Health
University of California, Berkeley
Electromagnetic Radiation Safety
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