镉经饮水染毒对去卵巢大鼠维生素D_3代谢的影响

Vitamin D_3 Metabolisms in Ovariectomized Rats Exposed to Cadmium via Drinking Water

[目的 ]探讨镉经饮水染毒对去卵巢大鼠维生素D3 代谢的影响。 [方法 ]将雌性 6月龄SD大鼠行人工去卵巢术 ,分别经饮水给不同剂量的镉 ,2 4周后处死。用放射免疫法测定 2 5 羟维生素D3 和 1,2 5 双羟维生素D3 ,石墨炉原子吸收法测定血、尿镉 ,放射免疫法测定血清雌二醇、甲状旁腺激素 ,同时测定肾功能指标尿 β2 微球蛋白、尿N 乙酰 β D 氨基葡萄糖苷酶和尿钙。 [结果 ]去卵巢大鼠体内雌二醇下降 ,甲状旁腺激素显著升高。经镉染毒的去卵巢大鼠体内 1,2 5 双羟维生素D3 的水平降低 ,且有剂量 效应关系。而各组血清 2 5 羟维生素D3 水平无明显差异。与对照组相比 ,各镉染毒组的尿钙、β2 微球蛋白及NAG水平均升高 ,高剂量组 (2 0 0mg/L)有显著性差异。血液 1,2 5 (OH) 2 D3 水平与肾小管损伤指标尿 β2 微球蛋白及尿钙呈显著性负相关。 [结论 ]结果提示镉接触能造成去卵巢大鼠维生素D3 代谢损害 ,主要使活性维生素D3 水平下降 。

To investigate vitamin D 3 metabolisms in ovariectomized rats exposed to cadmium via drinking water. Female Sprague Dawley rats aged 6 months were ovariectomized and administrated with the cadmium ion at the dose of 0,50,100,and 200 mg/L in drinking water.After 24 weeks,the levels of 1,25 dihydroxyvitamin D 3 and 25 hydroxyvitamin D 3 in serum were measured. Cadmium concentrations in urine and blood were assayed by an atomic absorption spectrophotometer,and contents of serum estradiol were detected by RIA. Urinary calcium,NAG and β 2 MG were used as the indicators of cadmium induced renal dysfunction. Compared to the control group,the ovariectomized rats had lower estradiol in serum. 1,25(OH) 2D 3 concentrations in serum were significantly decreased following increasing dose of cadmium. The concentrations of calcium, β 2 MG and NAG in urine were significantly higher after administration of cadmium at a dose of 200 mg/L. Significant negative correlation among 1,25(OH) 2D 3 concentrations,the cadmium level in rats and the urinary β 2 MG was observed. [Conclusion] Cadmium could disturb vitamin D3 metabolism in the ovariectomized rats,mainly inhibiting the synthesis of 1,25(OH) 2D 3,which was related to the cadmium induced renal damage.