Cognitive impairment and neurogenotoxic effects in rats exposed to low-intensity radiation (electrosmog)
The University of Delhi, India, conducted a relatively elaborate study in 2015 in which they exposed 24 rats to very low levels of electromagnetic radiation for 2 hours a day, 5 days a week.
The researchers, after 180 days of study, quantified the rats’ cognitive function, levels of heat shock protein 70, and DNA damage in brain cells.
The results showed a decline in cognitive function, elevated HSP70 levels and DNA damage in brain cells of animals exposed to electromagnetic radiation.
The study
A total of 24 rats were divided into 4 groups. Groups 2, 3 and 4 were subjected to low intensity electromagnetic radiation for 2 hours per day, 5 days per week, in a controlled environment. The first group, on the other hand, served as a control (sham control). In fact, the rats in this group were kept in the same environment as the other groups but with the microwave generator turned off. The 3 different frequencies to which groups 2, 3 and 4 were exposed and their relative specific absorption rates (SAR) are summarized in the table below [1].
| Group | Frequency (MHz) | SAR (W/Kg) |
|---|---|---|
| 1 | - | 0 |
| 2 | 900 | 5.953 · 10^-4 |
| 3 | 1800 | 5.835 · 10^-4 |
| 4 | 2450 | 6.672 · 10^-4 |
The frequencies selected for this study are used universally by telecommunications. For example, the 900 Mhz frequency is used for amateur radio. The 1800 Mhz is used for LTE data transmission and the 2450 Mhz frequency is used for amateur radio and satellite communications. These frequencies are therefore ubiquitous in our modern environment.
It is important to note that the EMF intensity used in this study is extremely low. The specific absorption rate (SAR) is approximately 6 - 10^-4 W/Kg for the three frequencies used. Simplifying the scientific notation, the SAR value is 0.0006 W/Kg. As seen in the last article, the SAR value for a standard phone call is about 1 W/Kg. This study used a SAR value 1666 times lower than the SAR value of a standard phone call.
In fact, this experiment investigates the biological effects of low-intensity exposure to electromagnetic radiation, not acute exposure. In today’s world many of us are exposed 24 hours a day, 7 days a week to varying intensities of electromagnetic radiation. Even when using their technological devices in a smart way (airplane mode and wired connections), many people are exposed to electrosmog from neighbors, telephone antennas, work environments, etc..
Cognitive Tasks
The cognitive function of the rats was quantified through two tests performed before and after the 180-day experiment. In the first test, called the Elevated Plus Maze, rats are placed in a cross stand with two open and two closed branches. In the University of Delhi study, mice were trained to walk from one end of an open branch to a closed branch before and after the 180-day period. The time required for the mouse to enter the closed branch was measured. The experiment was repeated 24 h after training to quantify the retention of information learned the day before. The longer it takes the mouse to enter a closed branch, the more learning and retention are impaired.
The second test, called the Morris Water Maze, involves placing the mouse in a small pool in which there is a hidden location below the water level where the mouse, if it reaches it, can lean and rest.
The time it takes to reach the platform after a training session is measured. Generally, the longer the time, the lower the cognitive performance of the mouse.
Results
Cognitive function
The results of the Elevated plus maze test show that all groups exposed to electromagnetic radiation have a higher time to perform cognitive tasks than the control group.
Effect of microwave exposure on congitive function of rats
- A: time taken by rats to enter one of the closed branches during training for the Elevated plus maze test (acquisition)
- B: time taken by rats to enter one of the closed branches 24h after training for the Elevated plus maze (retention) test
- *: shows a significant difference compared to the control group (sham) (P < .05)
Time measured on day 0 and day 180 indicated cognitive performance for task acquisition, whereas time measured on the next day, i.e., 24 h after day 0 or 24 h after day 180 quantified retention of information acquired during training.
Rats exposed to electromagnetic radiation took longer to enter one of the closed branches in the Elevated plus maze test than rats in the control group. This increase indicates a compromise in learning and memory.
In the Morris Water Maze test, a significant difference in the time it took to find the hidden platform was observed between the microwave-exposed groups and the control group.
Effect of microwave exposure on rat behavior
- C: time spent finding the hidden platform in the Morris Water Maze test.
- D: time spent in the hidden platform
- *: shows a significant difference compared to the control group (sham)(P < .05)
The microwave-exposed group required a significantly longer time to reach the platform than the control group. In addition, the time spent in the platform was significantly shorter for the radiation-exposed rats.
DNA
The Comet Assay has been used to quantify DNA damage to brain cells in mice. This assay is very interesting because it allows us to quantify DNA damage visually. In the images below we see what is described as a cometa. The more DNA is in the section of head, the left intense white part, the more intact and healthy the DNA is. Conversely, if a large portion of the DNA is in the tail, which is the less intense and longer shaped part on the right, the DNA is damaged.
A: control group (sham) B: 900 MHz exposure C: 800 MHz exposure D: 2450 MHz exposure
In the rat study, the percentage of DNA migrating to the tail region was significantly increased in all groups exposed to radiation. Similarly, the percentage of DNA in the head is significantly reduced in all groups exposed to microwaves.
Conclusion
The results showed a decline in cognitive function, elevated HSP70 and DNA damage in the brains of animals exposed to microwaves.
Also remember that we are not talking about strong intensities of electromagnetic radiation but very low intensities for only 2 hours a day. This study shows that a constant exposure to low intensity of electromagnetic radiation (electrosmog) causes cognitive impairment and DNA damage in brain cells.