ID Number		610
Study Type		In Vivo
Model		2450 MHz (CW) exposure to rats and mice and analysis of teratogenic and developmental effects
Details		Fischer 344 rats were mated and exposed to 2450 MHz (CW) microwaves at a whole-body average SAR of 2 W/kg (local brain SARs 6.0 W/kg, local colon SAR ~3.0 W/kg) for 3 h/d during days 5-20 of gestation. Pups were then exposed from day 2-20 after birth at whole-body SARs of ~16.5 (at 2 days) to ~5.5 W/kg (at 20 days). A series of behavioral/motor tests were then performed on days 30-32 and 100-102. Exposure resulted in a heavier body mass from preweaning until age 30, a reduced swimming endurance, and an increase in startle response to an air-puff stimulus. No effects were observed for motor activity, fore- and hindlimb grip strength, negative geotaxis, or reaction to an adverse thermal stimulus. In the 1983 Teratology paper, Sprague Dawley rats were exposed to 2450 MHz (CW) at 10 mW/cm2 for 3 h/d from day 4 of pregnancy through day 40 postpartum. The pregnant dams received a whole-body SAR of 1.76 W/kg. The SAR in the brain of the pups varied with body weight (19 W/kg at 15 days, 10 W/kg at 20 days, 9.7 W/kg at 30 days and 9.5 W/kg at 40 days of age). At 15, 20 30 and 40 days of age, multiple parameters of brain histopathology were evaluated including cortical architecture of cerebral cortex, decline of germinal layer along lateral ventricles, myelination of corpus callosum, and decline of external germinal layer of cerebellar cortex. In addiion, at 40 days of age, quantitative measurement of neurons was done (spine density on dendrites of pyramidal cells in cortex and number and density of Purkinje cells). No changes were observed on brain development due to embryonic, fetal, or postnatal RF exposure. In other studies, CD-1 mice were exposed to 2450 MHz (CW) MW 8 hr/day through days 1-6 or 6-15 of pregnancy at an SAR near the uterus of 40.2 W/kg. Exposure increased core temperature by 2.3 C after 40 minutes. Brain cholinesterase activity and histology were not affected by MW exposure. Although an initial report indicated a small but significant effect on fetal toxicity and teratogenicity, this was not confirmed in a subsequent report. The authors suggest that the 40.2 W/kg exposure level may be very close to the teratogenic threshold. In related studies, CD-1 mice (females induced to super-ovulate and mated) were also exposed to 2450 MHz (CW) MW for 3 hr on either day 2 or 3 of pregnancy at SARs (as estimated near the of the uterus) of 0.76-1.3 W/kg. In animals exposed at the highest level, core temperature increases of ~1 degree was recorded. No effects of MW exposure were observed on the development of preimplantation embryos or cytogenetic effects.
Findings		Effects (only at thermal levels)
Status		Completed With Publication
Principal Investigator		NIEHS, RTP North Carolina, USA
Funding Agency		NIEHS, USA
Country		UNITED STATES
References		Galvin, MJ et al. Bioelectromagnetics, (1986) 7:57-71 Nawrot, PS et al. Radiat. Res., (1985) 102:35-45 Inouye, M et al. Teratology, (1983) 28:413-419 Inouye, M et al. Bioelectromagnetics, (1982) 3:275-283 Nawrot, PS et al. Teratology, (1981) 24:303-314 McRee, DI et al. Environ. Health Perspectives, (1979) 30:123-131
Comments