Embryotoxicity of various noise stimuli in the mouse

Different noise exposure paradigms were studied to determine their teratogenic and embryo-fetotoxic potential in the CF-1 mouse. Female mice were exposed from days 1-6 or from days 6-15 of gestation to one of three noise exposure paradigms which differed widely in level, spectral, and temporal characteristics. Paradigms for noise exposure were chosen to represent semi-continuous exposure to extremely high-intensity noise (jet engine noise at 126 dBA, from noon to midnight); to represent startling type noise composed of alarm bells, jet engine noise, or narrow band warning devices at 110 dBA, with pseudorandom onset and duration of each controlled by a microprocessor (exposure time of 18% over each 24 hour period); and finally to represent very high frequency noise (18-20 kHz tones, derived from a device commercially marketed for repelling rodents, with exposure from noon to midnight). On day 18 of gestation the females were sacrificed, their reproduction status determined, and the concepti were examined for toxicity and for external, visceral, and skeletal alterations. Maternal plasma corticosterone levels were measured at different periods of gestation. Significantly decreased pregnancy rate was noted in all groups exposed to noise except in the group exposed to the very high frequency noise from days 6-15 of gestation. Significant embryolethal effects occurred in the group exposed to the extremely high intensity jet noise paradigm, from days 1-6 of gestation, and significant fetolethal effects occurred in the group exposed to the very high frequency noise paradigm from days 6-15 of gestation. No significant noise-related changes were noted in the incidence of structural alterations or in the concentration of plasma corticosterone.