90 fertilized eggs were divided into 6 groups (each group n=15): control group, sham exposure and four exposure groups exposed to different magnetic flux intensities (24 h before incubation). The hearts were removed on day 14 of embryonic development.
|Setup||42 cm long cylindrical coil with an inner diameter of 9.6 cm, an outer diameter of 11.5 cm and 980 turns of 2.5 mm enameled copper wire; five eggs placed horizontally in east-west direction in the coil; magnetic flux parallel to the long axis of the embryo's body; exposure chamber ventilated|
|Sham exposure||A sham exposure was conducted.|
Histomorphometric investigations of the lengths, widths, thickness of the septae, and left and right ventricles showed normal cells in the hearts of embryos of the control group and sham exposed group in comparison to those of the exposed groups: There was a significant decrease in the lengths of the hearts of exposure group 2 (2.66 mT) and a significant increase in the lengths of the hearts of exposed groups 3 (5.52 mT) and 4 (7.32 mT). Additionally, a significant decrease and increase were observed in the widths of the hearts of exposure group 2 and exposure groups 3 and 4, respectively, The thickness of septae of the hearts of exposed embryos of group 2 showed a significant decrease. There was a significant decrease in the thickness of the wall of the left ventricle in embryos of exposure group 2 and a significant increase in those of exposure groups 1, 3, and 4. The thickness of the wall of the right ventricles was significantly decreased in exposure group 2 while it had increased in the hearts of groups 1, 3, and 4. (All parameters in comparison with sham exposed and control group).
Extremely low frequency magnetic field exposure caused damaged myocytes in exposure group 1, condensed dark nuclei, an increase in the number of apoptotic cells in addition to increased intracellular spaces in exposure group 2, light inflammation and myocyte necrosis in exposure groups 3 and 4, an increase in the number of nuclear membranes' pores, small round unclear cristae mitochondria, and a decrease in the number of mitochondria in the myocytes of exposure group 4 as well as an increase in alkaline phosphatase activities in all exposure groups.
The data provided evidence that extremely low frequency magnetic fields damaged the hearts of chicken embryos at histological, cellular, biochemical level.