M. Murata et al., TERATOGENIC EFFECTS OF NOISE AND CADMIUM IN MICE - DOES NOISE HAVE TERATOGENIC POTENTIAL, Journal of toxicology and environmental health, 39(2), 1993, pp. 237-245
The teratogenkity of combined exposure to noise and cadmium was studie
d in mice. ICR mice were exposed to a wide octave-band of noise at 100
dB(C) for 6 h on d 7 of pregnancy in one of two ways: continuous expo
sure or intermittent (15 min on/15 min off). Cadmium sulfate at 1 or 2
mg/kg was intraperitoneally injected on d 7 of pregnancy. Four groups
were exposed to both cadmium and noise. On d 18 of pregnancy, fetuses
were examined for external and skeletal malformations. Another experi
ment was performed with two other patterns of noise exposure: continuo
us exposure for 3 h, and intermittent exposure (5 min on/5 min off) fo
r 6 h on d 7 of pregnancy. In the groups exposed to continuous noise f
or 6 h, total percentages of malformed fetuses were significantly high
er than that in the control group, but there were no significant incre
ases of total percentages of fetal malformations in the combined treat
ment groups in comparison with the groups given the same dose of cadmi
um alone. The percentages of skeletally malformed fetuses in groups ex
posed to 6 h of continuous noise were significantly higher than in gro
ups that received saline or the same dose of cadmium. There were no si
gnificant differences in the total percentages of malformed fetuses be
tween the control group and the groups exposed to a total of 3 h of no
ise, whether continuously or intermittently. Although combined treatme
nt with cadmium and noise resulted in an increase of total percentages
of malformed fetuses compared to the same dose of cadmium alone, the
interactions between cadmium and noise showed no synergistic effect on
teratogenicity. The magnitude of teratogenicity due to noise is much
weaker than that of cadmium, and is therefore easily masked by that of
cadmium in statistical tests of the significance of differences.