铅暴露对一氧化氮及氧自由基代谢的影响

Effect of lead exposure on metabolism of nitric oxide and oxygen free radical.

[目的]了解番禺地区儿童铅暴露情况,探讨高水平铅暴露对儿童血浆中一氧化氮(nitric oxide,NO)、一氧化氮合成酶(nitric oxide synthase,NOS)、超氧化物歧化酶(superoxide dismutase,SOD)、丙二醛(malondialdehyde,MDA)的影响,以及NO系统与氧自由基之间的相互关系.[方法]对440例1～3岁入托体检的健康儿童,测定其血铅、血浆NO、NOS、SOD及MDA水平.[结果]儿童血铅水平为(0.561±0.211)μmol/L,≥0.483μmol/L(100μg/L)者占51.14%;高水平铅暴露的儿童血浆NOS活性明显降低(P＜0.01),NO亦降低,但差异无显著性(P＞0.05);NOS与铅、SOD呈负相关,与NO呈正相关,而SOD与MDA呈负相关;以NOS作为因变量进行多元回归分析,回归方程为y'=4.228-5.309×血铅-0.083×SOD.[结论]环境铅污染对儿童已构成严重的威胁,应引起社会各界高度重视;高水平铅暴露儿童血浆中NOS活性受到明显抑制,使NO的生成减少,而且NOS活性与SOD活性存在有一定相关性.

【Objective】 To explore the lead exposure level in children aged 1 to 3 years, and determine the effect of lead exposure on serum nitric oxide （NO）, nitric oxide synthase（NOS）, superoxide dismutase（SOD）, malondialdehyde （MDA） and the relationship between NO systems and oxygen free radical. 【Method】 Vein blood samples for the levels of blood lead, plasma NO, NOS, SOD and MDA were taken from 440 health children. 【Results】 The mean of blood lead concentration for children was 0.561 μmol/L, 51.14% children had a blood lead level of ≥0.483 μmol/L. It was found that the children of high level lead exposure （blood lead≥0.483 μmol /L） had lower level of NOS （P〈0.01） and NO （P〉0.05） as compared to low level lead exposure in children. Plasma NOS activity was negatively related with either blood lead or SOD, and positively related with NO. SOD was negatively related with MDA. Multivariate ralated analysis showed Y＇=4.228-5.309×lead-0. 083×SOD while NOS as independent variahle. 【Conclusions】 The lead exposure level in children is so high that it is necessary to attach importance to prevent ehildren lead poisoning. The data suggest high level lead exposure can inhibit serum NOS activity thereby interfering in NO synthesis, and NOS activity is also affected by SOD activity.