TERATOGENIC EFFECTS OF NOISE AND CADMIUM IN MICE - DOES NOISE HAVE TERATOGENIC POTENTIAL

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.