The purpose of this study was to find out the protective effect of milk against cadmium poisoning and the degree of cadmium toxicity according to the administration time in the pregnant rats.
For the experiment, 125 pregnant rats of S. Prague-Dawley strain were used. The rats were divided into five groups-one control group, two cadmium alone treatment groups and two cadmium plus milk treatment groups. Cadmium was administered per os 60mg of CdC12 per Kg of body weight per day (60mg/Kg/day) for four consecutive days at the early stage (7th.loth day) and at the late, stage (14th~17th day) of gestation. Milk was administered ad libitum from the 5th day to the 20th day of gestation.
On the 20th day of gestation, the histopathological change of organs, the teratological abnormalities of fetuses, and the accumulation of cadmium were measured.
The results of the experiment were as follows
1. The fetal weight of the group treated with cadmium at the late stage reduced much more than that of the group treated at the early stage of gestation. It was observed that milk had the effect of preventing the fetal weight from reducing.
2. As for the amount of cadmium accumulation, it was highest in the liver. Then kidney, placenta and blood followed it in that order. Milk was observed to restrain the cadmium concentration in the maternal organ and the fetus. Cadmium concentration of the cadmium treatment group at the late stage of gestation was higher than that of the group treated at the early stage. Cadmium administered in the dam body was transferred´ only partially to fetus through the placenta.
3. The histopathological changes of the placenta and the fetal kidney were significantly different among the experimental groups. Placenta and fetal kidney of the rats treated with cadmium alone showed massive necrotic tissues, while cadmium plus milk ´´treatment decreased this necrosis.
4. Ossification of fetuses born of dams administered with cadmium orally was retarded. But fetal ossification of the cadmium, plus milk treatment group was similar to that of the control group. Some external, visceral and skeletal malformations were observed in the cadmium-treated groups.
In conclusion, this study revealed that the ´toxicity of cadmium was higher in, the group administered at the late stage of gestation than administered at the early stage. It was proved that milk reduce not only accumulation of cadmium in the various organs, but the histopathological damage of placenta sand fetal kidney, and the incidence rate of abnormalities as well.
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