64 rats were divided into 8 groups of rats: rats from groups 1-3 were administered manganese (60 mg, 15 mg, or 3.75 mg per kg body weight), rats from group 4 were exposed to a magnetic field, rats from group 5-7 were administered manganese (60 mg, 15 mg, or 3.75 mg per kg body weight) and exposed to a magnetic field, and group 8 was handled as a cage control. Manganese was administered daily during the exposure period.
Exposure duration: continuous for 4 h/day on 45 days
rats were divided into the following eight groups: 1.) administration of 60 mg/kg Mn 2.) administration of 15 mg/kg Mn 3.) administration of 3.75 mg/kg Mn 4.) EMF exposure 5.) administration of 60 mg/kg Mn + EMF exposure 6.) administration of 15 mg/kg Mn + EMF exposure 7.) administration of 3.75 mg/kg Mn + EMF exposure 8.) cage control
|Exposure duration||continuous for 4 h/day on 45 days|
|magnetic flux density||1 mT||-||-||-||-|
In rats that received 60 mg or 15 mg manganese per kg body weight daily (group 1, 2, 5, 6), the bone density in the anterior jaw was significantly increased after the exposure/treatment period compared to before. In the cranium, the bone density was significantly increased in group 1, 4, and 5 after the 45 days of treatment compared to the starting value. When the treatment groups were compared to the cage control after 45 days, the bone density of all rats was significantly increased in the anterior jaw and in the whole cranium.
While the oral tissue of the cage control group appeared normal, magnetic field exposed groups (group 4-7) showed histopathological alterations (dilated blood vessels, changes in the connective tissue). Additionally, in oral tissue of rats that were administered manganese (group 1-2) histopathological changes (in connective tissue) occurred, while samples of group 3 appeared almost normal.
The authors conclude that extremely low frequency magnetic fields and manganese could influence the bone density of the rat jaw and cranium, but that further studies are required to confirm the results.