Medical/biological study (experimental study)

A 60 Hz magnetic field does not affect the incidence of squamous cell carcinomas in SENCAR mice med./bio.

By: McLean JR, Thansandote A, McNamee JP, Tryphonas L, Lecuyer D, Gajda G

Published in: Bioelectromagnetics 2003; 24 (2): 75-81

Aim of study (acc. to author)

To investigate possible promoting or co-promoting effects of a 60 Hz magnetic field exposure in the SENCAR mouse model.

Background/further details

DMBA and PMA (phorbol myristate acetate) were used for the chemical induction of skin tumors. A total of 96 mice were used in this study (2 groups/48 animals each). One group served as a sham-exposed control. Tumor development was initiated with a single dose of DMBA (10 nmol) and mice were treated with PMA (phorbol myristate acetate, 3 µg) once a week thereafter. First administration of PMA and the magnetic field exposure started one week after the initial DMBA treatment. PMA treatment was continued for 23 weeks and the magnetic field exposure for additional 29 weeks (i.e. a total of 52 weeks of exposure or sham-exposure, respectively).

Endpoint

cancer: skin tumors

Exposure

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: 6 h/day, 5 day/week for 52 weeks	magnetic flux density: 2 mT mean (unspecified) magnetic flux density: 235 nT mean (unspecified) (0.140 µT; with the coils inactive in the chambers)

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Exposure duration	6 h/day, 5 day/week for 52 weeks

Exposure setup

Exposure source	4 x 4 Merritt coil sets with 40 cm x 40 cm square coils of 84:36:36:84 turns
Chamber	two Quad/4x Exposure chambers
Additional info	Each chamber held 4 exposure cages constructed from 6 mm plastic, each cage 39.4 cm x 26.0 x 14.9 cm further subdivided into 4 exposure suits, each suit 9.88 cm x 26 cm x 14.9 cm capable of holding 3 mice.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	2 mT	mean	measured	unspecified	-
magnetic flux density	235 nT	mean	measured	unspecified	0.140 µT; with the coils inactive in the chambers

Reference articles

McLean JR et al. (1997): The effect of 60 Hz magnetic fields on co-promotion of chemically induced skin tumors on SENCAR mice: a discussion of three studies

Exposed system:

animal
mouse/SENCAR
whole body

Methods Endpoint/measurement parameters/methodology

cancer: skin tumors; tumor counts in vivo
morphol./histopathol. changes: histopathological evaluation of skin tumors (tissue slices, hematoxylin-eosin stain)
body weight

Investigated system:

tissue slices
investigation on living organism

Investigated organ system:

skin

Time of investigation:

during exposure
after exposure

Main outcome of study (acc. to author)

No differences were found between the two groups. Neither the development of papillomas nor squamous cell carcinomas were influenced under the experimental conditions of this study.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Soffritti M et al. (2016): Synergism between sinusoidal-50 Hz magnetic field and formaldehyde in triggering carcinogenic effects in male Sprague-Dawley rats
McLean JR et al. (1997): The effect of 60 Hz magnetic fields on co-promotion of chemically induced skin tumors on SENCAR mice: a discussion of three studies
McLean J et al. (1995): A 60-Hz magnetic field increases the incidence of squamous cell carcinomas in mice previously exposed to chemical carcinogens
Stuchly MA et al. (1992): Modification of tumor promotion in the mouse skin by exposure to an alternating magnetic field
McLean JR et al. (1991): Cancer promotion in a mouse-skin model by a 60-Hz magnetic field: II. Tumor development and immune response