Medical/biological study (experimental study)

Stereological analysis of thyroid mast cells in rats after exposure to extremely low frequency electromagnetic field and the following "off" field period med./bio.

By: Rajkovic V, Matavulj M, Lazetic B

Published in: Acta Biol Hung 2005; 56 (1-2): 43-51

Aim of study (acc. to author)

The influence of extremely low frequency electromagnetic field on thyroid gland mast cells should be investigated on male rats.

Background/further details

Forty-seven animals were exposed from 24 hours after birth. 12 animals each were sacrificed directly (group 1), one week (group 2), two weeks (group 3), and 11 rats three weeks (group 4) after the last day of exposure. The control group consisted of 42 rats.

Endpoint

morphol./histopathol. changes: effects on thyroid gland mast cells

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 7 h/day, 5 days/week for 3 months starting 24 h after birth	electric field strength: 10 V/m magnetic flux density: 500 µT maximum (on the cage side near the coil) magnetic flux density: 50 µT minimum (on the opposite cage side)

Exposure 1

Main characteristics

Frequency	50 Hz
Type	electric field magnetic field
Exposure duration	7 h/day, 5 days/week for 3 months starting 24 h after birth

Exposure setup

Exposure source	coil(s)
Setup	coil consisting of 1320 turns of 2.5 mm copper wire wound round a wooden frame; cages placed symmetrically on both sides of the coil

Parameters

Measurand	Value	Type	Method	Mass	Remarks
electric field strength	10 V/m	-	measured	-	-
magnetic flux density	500 µT	maximum	measured	-	on the cage side near the coil
magnetic flux density	50 µT	minimum	measured	-	on the opposite cage side

Exposed system:

animal
rat/Mill Hill
whole body

Methods Endpoint/measurement parameters/methodology

morphol./histopathol. changes: numerical and volume density of total thyroid gland mast cells (toluidine blue-stain, light microscope); mastcell classification: type A (compact cells with abundant cytoplasmatic granules, type B (cells with numerous cytoplasmatic extensions), type C (degranulated cells with extruded granules in intercellular space)

Investigated system:

isolated organ
thyroid gland

Investigated organ system:

thyroid gland

Time of investigation:

after exposure

Main outcome of study (acc. to author)

After three months exposure an increased volume density of degranulated (mediator releasing) mast cells (type C) were found in all exposure groups, except in group 3 (two weeks recovery period after the exposure). The numerical density of type C mast cells was increased as well.The ratio of the numerical density and of the volume density of type B mast cells to type C mast cells was lower in all exposed groups as compared to the control groups. The exception was group 2 (one week recovery period) with similar values of the ratio of the volume density in exposure group compared to control group.
These results implicate the sensitivity of thyroid gland mast cells to power frequency electromagnetic fields.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Ministry of Science and Technology, Serbia

Rajkovic V et al. (2010): Combined exposure of peripubertal male rats to the endocrine-disrupting compound atrazine and power-frequency electromagnetic fields causes degranulation of cutaneous mast cells: a new toxic environmental hazard?
Rajkovic V et al. (2010): Studies on the synergistic effects of extremely low-frequency magnetic fields and the endocrine-disrupting compound atrazine on the thyroid gland
Rzewnicki I (2008): [Activity of vestibular organ in people using mobile phones professionally]
Rajkovic V et al. (2006): Light and electron microscopic study of the thyroid gland in rats exposed to power-frequency electromagnetic fields
Rajkovic V et al. (2005): Histological characteristics of cutaneous and thyroid mast cell populations in male rats exposed to power-frequency electromagnetic fields
Rajkovic V et al. (2003): Evaluation of rat thyroid gland morphophysiological status after three months exposure to 50 Hz electromagnetic field
Rajkovic V et al. (2001): Morphophysiological status of rat thyroid gland after subchronic exposure to low frequency electromagnetic field
Cook LL et al. (2000): Differential effects of low frequency, low intensity (
Matavulj M et al. (2000): Studies on the possible endocrinological effects of a 50 Hz electromagnetic field
Price JA et al. (1998): Analysis of the effect of a 60 Hz AC field on histamine release by rat peritoneal mast cells