镧影响大鼠学习记忆及海马c-fos基因、CA1区c-Fos蛋白表达的研究

Study of the effects of lanthanum on learning,memory,c-fos gene and c-Fos protein expression in CA1 area of hippocampus in rats

目的探讨镧对大鼠学习记忆能力和即刻早期基因表达的影响。方法随机将40只雌大鼠分为对照组和低、中、高剂量染镧组,各染镧组仔鼠在出生至断乳后1个月染镧,然后进行水迷宫和穿梭箱测试,并测定海马c-fos基因、CA1区c-Fos蛋白和尼氏体表达水平。结果神经行为学测试时,染镧组仔鼠的学习记忆能力明显低于对照组,具有一定的剂量-效应关系;低、中剂量染镧组仔鼠海马c-fos mRNA和CA1区c-Fos蛋白表达水平明显低于对照组,高剂量染镧组仔鼠海马c-fos mRNA和CA1区c-Fos蛋白表达水平明显低于对照和低剂量染镧组;随镧染毒剂量增加,仔鼠海马CA1区神经元胞质中尼氏体明显减少,且高剂量染镧组仔鼠海马CA1区部分细胞胞质中尼氏体消失,存在细胞空泡变性。结论镧损害大鼠学习记忆能力的机制可能与LaCl3造成海马即刻早期基因c-fos基因和蛋白表达水平降低、神经元功能减弱有关。

Objective To study the effects of lanthanum on learning, memory and immediate early gene expression. Methods Female rats were divided randomly into four groups： control, low-, middle-, and high-dose lanthanum groups. Pups of lanthanum groups were administrated with lanthanum from birth to weaning for one month. Learning and memory of pups were measured by neuroethology testing. C-fos gene, c-Fos protein and Nissl body expression in CA1 area of hippocampus in pups were also detected. Results In the neuroethology testing, learning and memory of pups in lanthanum groups were significantly lower than those in control group, and show dose-effect relationship to a certain extent. C-fos gene and c-Fos protein expression in CA1 area of hippocampus in low- and middle-dose lanthanum group pups were lower significantly than those in control group, and the levels of high-dose lanthanum group pups were lower significantly than those of control and low-dose lanthanum group. Nissl body in CA1 area of hippocampus decreased with lanthanum dose increasing, and the levels of Nissl body in CA1 area of hippocampus in high-dose lanthanum group pups decreased as compared with control and low-dose lanthanum group. Besides, Nissl body in CA1 area of hippocampus disappeared in some cells of high-dose lanthanum group pups. Conclusion lanthanum could injure learning and memory of rats, which was related to low level of hippocampal c-fos gene, protein expression and neuronal function induced by lanthanum.