Medical/biological study (experimental study)

Photoperiodism as a modifier of effect of extremely low-frequency electromagnetic field on morphological properties of pineal gland med./bio.

By: Lukac T, Matavulj A, Matavulj M, Rajkovic V, Lazetic B

Published in: Bosn J Basic Med Sci 2006; 6 (3): 10-16

Aim of study (acc. to author)

The aim of this study was to determine whether photoperiodism has any impact on the effects that three-month long exposure to extremely low frequency electromagnetic field has on morphological characteristics of rat's pineal gland.

Background/further details

The exposure was carried out on 24 male rats starting 24 hours upon birth until their sexual maturity. The control group consisted of 24 male rats as well. The study was performed both during summer and winter, following the identical protocol. Six animals each per exposure group and control group were investigated first in each season (summer/winter) directly after exposure (group I) and second after three weeks of exposure (group II).

Endpoint

effects on the neurological system: morphological and stereological changes in pineal gland

Exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 7 h/day, 5 days/week for 3 months	magnetic flux density: 50 µT minimum (50 µT - 500 µT) magnetic flux density: 500 µT maximum electric field strength: 10 V/m

Exposure 1

Main characteristics

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

Exposure setup

Exposure source	coil(s)
Setup	coil with 1320 turns of 2.5 mm wire; animal cages placed on both sides of the coil on wooden boards with rubber base
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	50 µT	minimum	-	-	50 µT - 500 µT
magnetic flux density	500 µT	maximum	-	-	-
electric field strength	10 V/m	-	-	-	-

Exposed system:

animal
rat/Mill Hill
whole body

Methods Endpoint/measurement parameters/methodology

morphol./histopathol. changes: see "effecs on the neurological system"
effects on the neurological system: morphological and stereological changes in pineal gland (e.g. volume densities of nuclei, cytoplasm, and pinealocytes): hematoxylin-eosin stain, light microscopy

Investigated system:

isolated organ
pineal gland

Investigated organ system:

neuroendocrine system

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Concerning wintertime, the most significant morphological changes in pineal gland in group I of exposed rats were: hyperemia, reduced pinealocytes with pale pink, poor cytoplasm and irregular, stick-form nuclei. In group II pinealocytes were enlarged, with vacuolated cytoplasm and hyper chromatic, enlarged nucleus. Morphological changes of the pineal gland in the summer were not as intense as in the winter and finding in the group II was comparable with those from the control group.
Stereological investigations revealed a decrease of volume density of pinealocytes, their cytoplasm and nuclei in group I both in winter and summer. In group II in winter, a volume density increase of pinealocytes, cytoplasm and nuclei was found.
These results indicate that photoperiodism is a modifier of the effect of extremely low frequency electromagnetic field on morphological structure of pineal gland, as the gland recovery was incomplete in winter and reversible in summer.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Matsushima S et al. (1993): Effect of magnetic field on pineal gland volume and pinealocyte size in the rat
Gimenez-Gonzalez M et al. (1991): Morphometric and structural study of the pineal gland of the Wistar rat subjected to the pulse action of a 52 Gauss, (50 Hz) magnetic field. Evolutive analysis over 21 days