식이내 Calcium 수준이 흰쥐의 Cadmium 중독에 미치는 영향

Abstract

This study was performed to investigate the effect of cadmium toxicity and different Ca levels on the effect of cadmium toxicity and on Car Cu, Zn metabolism in rats. Forty-eight rats of Sprague-Dawley strain weighing 137 ± 13 g were blocked into 6 groups according to body weight. Cadmium chloride was given at levels of 0 or 0.040%, Calcium were given at levels of 0.1%, 0.52%, 1.3%. The results are summarized as follow. 1) Food intake, weight gain, food efficiency ratio, liver and kidney weight, weight and length of bones, femur ash content in Cd-added groups were lower than those in Cd-free groups. 2) Cardmium content in liver, kidney, femur were significantly increased by Cd addition. 3) Ca, Cu, Zn contents in liver, Ca and Cu contents in kidney were increased by Cd addition. 4) Ca content was decreased by Cd addition but Cu content was increased. Therefore it seems that bone mineral composition was changed by Cd addition. 5) Daily urinary Ca and Cu excretion were increased by Cd addition but Zn excretion was decreased. Daily fecal Ca excretion was increased bf Cd addition but Cu excretion was decreased. 6) Fecal Cd excretion was increased in high Ca-Cd added group but liver, kidney, femur Cd accumulation were decreased. 7) Ca content in liver, kidney, femur, daily urinary and fecal Ca excretion were increased in high Ca diet groups. Ca content in kidney was increased in high Ca diet group. Cu content in liver was increased by Cd and Ca interaction. Zn content in blood and femur were decreased in high Ca diet group but urinary and fecal Cu, Zn excretion were increased. In conclusion, Ca absorption was decreased by Cd addition but Ca, Cu, Zn contents in liver were increased. As fecal Cd excretion was increased with increasing dietary Ca level, Cd retention ratio in body and Cd content in tissue were decreased. Therefore high Ca intake seemed to alleviate Cd toxicity.;본 연구에서는 식이를 통해 Cadmium(Cd)을 공급했을때의 Cd 중독효과와 식이 Ca수준이 흰쥐의 Cd중독에 미치는 영향 및 Ca과 Cu, Zn대사를 알아보기 위하여 평균체중이 137±3 g인 Sprague-Dawley종, 수컷 흰쥐 48마리를 식이 CdCl_(2)수준(0,0.04%)과 식이Ca 수준(0.1% 0.52%, 1.3%)에 따라 총 6군으로 나누어 4주간 사육하였다. 그 결과는 다음과 같이 요약된다. 식이를 통하여 Cd를 공급했을때 식이섭취량과 체중증가량, 식이효율이 감소하였으며 간과 신장의 무게, 뒷다리뼈의 무게와 길이 및 대퇴골의 회분함량이 감소하였다. 그리고 간과 신장, 대퇴골에 Cd이 축적되었고 간의 Ca과 Cu, Zn농도가 증가하고 신장의 Ca과 Cu농도가 증가하였으며 대퇴골의 Ca농도는 감소하고 Cu농도는 증가하여 bone mineral composition의 변화를 보였다. 또한 Cd의 공급은 뇨를 통해 Ca과 Cu배설을 증가시키고 Zn배설은 감소시켰으며 변으로 Ca배설을 증가시키고 Cu배설은 감소시켜 Cz과 Cu, Zn대사에 변화를 나타냈다. 고Ca식이섭취시에는 변을 통한 Cd배설이 현저히 증가했고 간과 신장, 대퇴골에 Cd축적이 감소하였다. 또한 간, 신장, 대퇴골의 Ca농도와 뇨와 변을 통한 Ca배설이 증가하였고, 신장의 Cu농도가 증가했고 간에서는 Cd공급과 식이Ca수준의 상호작용으로 Cu농도가 증가했으며 혈액과 대퇴골의 Zn농도가 감소하고 뇨와 변을 통한 Cu와 Zn배설이 증가하였다. 결론적으로 식이내 Cd공급시 체내 Ca흡수가 감소하였고 간의 Ca과 Cu, Zn농도는 증가되었다. 또한 식이Ca수준이 높을수록 변으로의 Cd배설이 증가됨으로써 체내 Cd보유율이 감소하였고 조직내 Cd농도도 감소하였다. 따라서 고Ca식이 공급시 Cd독성이 완화되는 것을 볼 수 있었다.