大鼠脑组织中轻稀土元素含量相关性研究

Study on correlation of contents of light rare earth elements in rats′ brains

研究了轻稀土元素La、Ce、Pr、Nd、Sm、Eu、Gd在大鼠脑组织中的吸收规律和蓄积特点。将雄性SD大鼠随机分为空白、对照、低、中、高及排毒组,每组10只,4周后处死,取脑组织。排毒组停止灌胃后继续饲养4周后处死取脑组织。用ICP-MS测定脑组织中上述稀土元素含量并做统计学分析。结果表明低、中、高剂量组大鼠脑组织中轻稀土元素含量逐渐增高,排毒组介于中、高剂量组之间;脑组织中轻稀土元素的含量远低于其他脏器;La、Ce、Pr在脑中分布符合奥多-哈尔金斯规则,Nd元素呈负偏离;多数轻稀土元素在脑和毛发中含量相关系数较高。稀土元素在脑组织中蓄积有量效关系,且蓄积具有可逆性;血-脑屏障对稀土元素的通透有一定阻碍作用;稀土元素在脑组织中的蓄积率不受摄入量的影响;毛发比全血更适合作为脑组织轻稀土元素含量的生物标志物。

The characteristics of accumulation and distribution of light rare earth element （LRees） in rats＇ brains were studied. Based on animal weight, 60 healthy male SD rats were randomly divided into two control groups and four experimental groups. After four weeks＇ feeding, the brains were collected except the group High- Ⅱ . The High- Ⅱ group was fed for another four weeks without citrate LRees. The inductively coupled plasma mass sqectrometer （ICP-MS） was employed for the determination of the element concentration in the brains. Results： 1. The concentrations of LRees in brain increased with the increase of the doses. 2. The concentrations of LRees of the group High- Ⅱ between the group High- Ⅰ and the group middle, and there was significant difference among the three groups （ P 〈 0.05）. 3. The concentrations of LRees in brains were far lower than those it in other organs. 4. The distribution pattern of La, Ce, Pr in the brains approximates to odd harkins＇ rule, but the Nd has a phenomenon of negative deviation. 5. The correlation coefficients of LRee concentrations between hair and brain were about 0.75, while those between blood and brain were very low and have no significance. Conclusions： 1. Dose-response relationship exists in the accumulation of LRees in brain, and the accumulation is reversible. 2. Blood-brain barrier can obstruct the accumulation of LRees in the brain to some extent. 3. The accumulation ratio of LRees in brain is not affected by the dose of treatment. 4. As a biomarker of the LRees in brain, hair is better than blood.