Medical/biological study (experimental study)

50 Hz magnetic fields activate mussel immunocyte p38 MAP kinase and induce HSP70 and 90 med./bio.

By: Malagoli D, Lusvardi M, Gobba F, Ottaviani E

Published in: Comp Biochem Physiol C Toxicol Pharmacol 2004; 137 (1): 75-79

Aim of study (acc. to author)

To investigate the cumulative effect of repeated exposures to extremely low frequency magnetic fields at different intensities on immunocyte functionality.

Background/further details

Mussels (groups of 5 animals) were exposed to 50 Hz magnetic fields with various intensities and different times.

Endpoint

cell function: immunocyte functionality

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: 30 min - once, twice or thrice with an interval of 3 h	magnetic flux density: 300 µT magnetic flux density: 400 µT magnetic flux density: 600 µT

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Exposure duration	30 min - once, twice or thrice with an interval of 3 h

Exposure setup

Exposure source	Helmholtz coils
Setup	pair of Helmholtz coils consisting of two horizontal PVC coated coils (10 cm x 10 cm, 1400 turns of 0.2 mm copper wire), separated by 13 cm
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	300 µT	-	measured	-	-
magnetic flux density	400 µT	-	measured	-	-
magnetic flux density	600 µT	-	measured	-	-

Exposed system:

invertebrate
mussel/Mytilus galloprovincialis
whole body

Methods Endpoint/measurement parameters/methodology

cell function: immunocyte functionality (expression of heat shock protein HSP70 and HSP90, phosphorylation of p38 MAP kinase [Western blot and densitometric evaluation])

Investigated system:

isolated bio./chem. substance
cell lysate

Investigated organ system:

immune system

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Animals exposed at 300 µT for three different times did not show differences in the heat shock protein expression in comparison with non-exposed mussels. At 400 µT, exposed animals showed a time-dependent increase in heat shock protein expression. After exposure to 600 µT, the heat shock protein expression was significantly higher than controls but independently from exposure duration. The induction of heat shock proteins is concomitant with the activation of p38 MAP kinase signalling pathway. The p38 MAP kinase phosphorylation was just as well intensity-dependent but independent of the time of exposure.
The findings suggest the possibility to modulate the expression of heat shock proteins by magnetic field exposure. Only the exposure to a magnetic field strength of 400 µT at all three durations sorted a cumulative effect and resulted in a gradual increase of HSP70 and HSP90 expression.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Ministero del Lavoro e delle Politiche Sociali (Ministry of Labour and Social Policies), Italy
Ministero dell' Università e della Ricerca (MIUR (formerly MURST (Ministero dell' Università e della Ricerca Scientifica e Tecnologica); Ministry of University and Research), Italy

Bernardini C et al. (2007): Effects of 50 Hz sinusoidal magnetic fields on Hsp27, Hsp70, Hsp90 expression in porcine aortic endothelial cells (PAEC)
Gottwald E et al. (2007): Expression of HSP72 after ELF-EMF exposure in three cell lines
Kanitz MH et al. (2007): Investigation of protein expression in magnetic field-treated human glioma cells
Alfieri RR et al. (2006): Increased levels of inducible HSP70 in cells exposed to electromagnetic fields
Coulton LA et al. (2004): Effect of 50 Hz electromagnetic fields on the induction of heat-shock protein gene expression in human leukocytes
Kang KI et al. (1998): Luciferase activity and synthesis of Hsp70 and Hsp90 are insensitive to 50Hz electromagnetic fields
Goodman R et al. (1998): Magnetic field stress induces expression of hsp70