钙对儿童铅毒性的干预作用实验研究和临床验证

NTERVENING ROLE OF CALCIUM ON LEAD TOXICITY IN CHILDREN EXPERIMENTAL STUDY AND CLINICAL VERIFICATION

迄今为止的国内外研究均巳表明,在现阶段,环境铅污染已经成为影响儿童生长发育的重要因素,而且铅毒性一旦发生,即难逆转,因此,预防比治疗具有更重要更积极的意义。从环境医学的角度出发,最根本的预防措施是消除环境铅污染或脱离铅污染环境,但这在目前尚不能做到,而在现有条件下,对铅污染地区高危儿童采取预防性给药,尽可能减少铅的吸收,是较为现实可行的措施。我们在建立动物模型的的基础上发现,在铅暴露同时补以等量钙能明显减低铅暴露幼鼠的血铅水平,其学习记忆能力亦几乎不受损害。在此基础上,我们进行了服用钙剂后自身前后血铅水平比较的临床验证,结果提示,铅圬染区儿童服用钙剂1个月后,86％的儿童血铅值有不同程度的下降,平均降幅达0.50μuml/L,血铅过高的儿童从服药前的50％下降到3％,这一结果证实了钙能有效抑制铅的吸收过程,为此,我们认为,对处于铅污染环境而暂时无条件脱离环境的早幼儿童应常规服用钙剂,以减轻铅对生长发育的损害。

The Purpose of this study was to evaluate the effect of calcium on lead toxic-ity both in mice and young children. 30 mice were devided into 3 groups at random: Group Ⅰ mice were administered orally with 5% Pb acetate. Group Ⅱ mice were administered similarly with both 5% Pb acetate and 5% Ca gluconate. Group Ⅲ served as control. After 35 days, the mean blood lead levelof three groups was 220 ug/L, 174 ug/L and 161 ug/L, respectively. The learning ability of control and Pb plus Ca -treated mice was significant better than that of Group I mice in step down test and maze test. In order to verify this result, 35 children, aged from 49 to 73 month old, from lead polluted area were selected to enter the study with previously permission by their parents. The average blood lead level was 245 ug/L, after one month' s treatment of Gai Tianli with the dose of 75 mg/day, the average blood lead level declined to 141 ug/L ( P <0. 01). We concluded that calcium could intervene the lead tox-icity in both mice and children. It was deduced that calcium supplement would benefit the children who unfortunately lived in the lead polluted area.