4 groups of rats were examined: 1.) sham exposure, treated with saline injection, 2.) sham exposure, injection of 2 mg melatonin per kg body weight, 3.) exposure and 4.) exposure, injection of 2 mg melatonin per kg body weight (21 rats per group). After 20, 40 and 60 days, seven animals of each group were anesthetized and killed after removing the thymus.
Exposure duration: continuous for 4 hours/day on 20, 40 or 60 consecutive days
|Setup||mobile phone was placed in a small perforated polycarbonated box in the center of the cage; seven freely moving rats per cage were placed on absorbing material made of rubber with wooden isolation surface|
|Sham exposure||A sham exposure was conducted.|
|Additional info||exposure was performed in the same room where all animals were housed or in another room (remark EMF-Portal: contradictory statements)|
|magnetic flux density||4.68 µT||minimum||estimated||-||-|
|magnetic flux density||8.69 µT||maximum||estimated||-||-|
|electric field strength||9.88 V/m||minimum||estimated||-||-|
|electric field strength||18.356 V/m||maximum||estimated||-||-|
In the exposed groups without melatonin (after 20, 40 and 60 days), the level of lipid peroxidation and protein oxidation, as well as the enzyme activities of catalase, xanthine oxidase, DNAse I and DNAse II were significantly increased compared to the control group. An administration of melatonin prevented these effects in the exposed group (except for the protein oxidation after 20 and 40 days).
The number of apoptotic cells was significantly increased in the exposed groups without melatonin compared to the control group. Moreover, the number of apoptotic cells increased with longer exposure duration. An administration of melatonin significantly reduced the apoptosis rate in the exposed group. The proliferation of the thymocytes was significantly decreased in the exposed groups without melatonin in comparison to the control group. This effect was stronger the longer the rats had been exposed. An administration of melatonin significantly increased the proliferation rate in the exposed group when compared to the exposed group without melatonin injection.
The authors conclude that melatonin could have a protective effect against oxidative stress and could modulate processes of apoptosis and proliferation in thymus tissue of microwave-exposed rats.