Medical/biological study (experimental study)

Effects of 50 Hz extremely low frequency sinusoidal magnetic fields on the apoptosis of the hearts of preincubated chicken embryos at different levels of developments med./bio.

By: Shams Lahijani M, Tehrani DM, Fereydouni N

Published in: Int J Radiat Biol 2013; 89 (4): 234-242

Aim of study (acc. to author)

To study the effects of 50 Hz sinusoidal extremely low frequency magnetic fields on preincubated chicken embryo hearts at histopathological, biochemical, and ultrastructural levels.

Background/further details

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.

Endpoint

effects on the cardiovascular system: embryonic heart development

Exposure

- 50 Hz
- 50/60 Hz
- magnetic field
- low frequency

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 24 h	magnetic flux density: 1.33 mT (group 1) magnetic flux density: 2.66 mT (group 2) magnetic flux density: 5.52 mT (group 3) magnetic flux density: 7.32 mT (group 4)

General information

Fertilized eggs were divided into the following six groups: 1) exposure to 1.33 mT 2) exposure to 2.66 mT 3) exposure to 5.52 mT 4) exposure to 7.32 mT 5) control group 6) sham exposure

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 24 h

Exposure setup

Exposure source	coil(s)
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.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	1.33 mT	-	measured	-	group 1
magnetic flux density	2.66 mT	-	measured	-	group 2
magnetic flux density	5.52 mT	-	measured	-	group 3
magnetic flux density	7.32 mT	-	measured	-	group 4

Exposed system:

animal
chicken embryos (eggs)
whole body

Methods Endpoint/measurement parameters/methodology

effects on the cardiovascular system: embryonic heart development (length, width, thickness of left and right ventricles and septae (hematoxylin-eosin stain); apoptosis (TUNEL assay); alkaline phosphatase enzyme activity (spectrophotometry); ultrastructural changes (transmission electron microscopy))

Investigated system:

tissue slices
heart homogenates

Investigated organ system:

cardiovascular system

Time of investigation:

after exposure

Main outcome of study (acc. to author)

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.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

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