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目的 观察长期低铅暴露对大鼠学习及记忆功能的影响并探讨其可能的机理。方法 选择刚断乳的Wistar大鼠 2 0只 ,随机分为实验组 (n =13)和对照组 (n =7) ,分别饮用 0 0 5%醋酸铅水溶液和蒸馏水。饲养10 0～ 110d后用Y迷宫检测分辨学习及记忆能力 ,然后取血和脑行铅、钙含量的测定。结果 慢性低铅接触后大鼠的学习能力 (2 0 2 3± 5 52 )和记忆保持百分数 (6 4 17± 9 92 )均显著低于正常对照组 (分别为 13 86± 1 95,86 6 7± 5 16 ) ,(P <0 0 1,t =2 95,2 98)。染铅大鼠血铅 (0 399± 0 82 ) μg/ml、脑铅 (2 189± 0 818) μg/g湿重 ,浓度均显著高于对照组 (0 0 4 93± 0 0 12 μg/ml,0 6 9± 0 0 8μg/g湿重 ) ,(P <0 0 1,t =10 94和 4 4 1) ;而两组间血钙和脑钙差异无显著性。学习记忆能力与血铅、脑铅含量有关。结论 慢性铅接触可损害大鼠的学习记忆功能 ,铅通过血脑屏障沉积于大脑并与钙离子拮抗 ,干扰了细胞内的钙稳态 ,是造成脑损害的机制之一。
Objective To observe the effects of long-term low lead exposure on learning and memory in rats and to explore its possible mechanism. Methods Twenty weanlings of Wistar rats were randomly divided into experimental group (n = 13) and control group (n = 7), respectively, with 0 05% aqueous lead acetate solution and distilled water. Feeding 10 0 ~ 110d after Y maze test to distinguish learning and memory ability, and then take blood and brain determination of lead, calcium content. Results The learning ability (2 0 2 3 ± 5 52) and memory retention (6 4 17 ± 9 92) of rats after chronic low lead exposure were significantly lower than those of the normal control group (13 86 ± 1 95, 86 6 7 ± 5 16), (P <0 0 1, t = 2 95, 2 98). The levels of blood lead (0 399 ± 0 82) μg / ml and brain lead (2 189 ± 0 818) μg / g wet weight and concentration in lead-exposed rats were significantly higher than those in control group (0 0 93 93 ± 0 0 12 μg / ml and 0 6 9 ± 0 0 8μg / g wet weight) (P <0.01, t = 10 94 and 4 4 1). There was no significant difference in serum calcium and brain calcium between the two groups. Learning and memory ability and blood lead, brain lead content. Conclusion Chronic lead exposure can impair the learning and memory function of rats. Lead deposits on the brain through the blood-brain barrier and antagonizes with calcium ions, interferes with intracellular calcium homeostasis and is one of the mechanisms that cause brain damage.