丰富环境对锰中毒小鼠学习记忆能力和神经发生的影响

Effects of enriched environment on learning and memory and neurogenesis of manganese exposed mice

目的:探讨丰富环境和贫瘠环境干预对锰中毒小鼠学习记忆能力和神经发生的影响。方法:成年昆明雌性小鼠40只,随机分成四组:空白对照组(对照组,CG)、正常环境染锰组(染锰组,SEG)、丰富环境干预染锰组(丰富组,EEG)、以及贫瘠环境干预染锰组(贫瘠组,IEG),每组10只。采用腹腔注射3周氯化锰(MnCl2 20mg/kg)的方式造模,Morris水迷宫检测小鼠学习记忆能力,免疫荧光法检测小鼠SVZ和SGZ内DCX的表达。结果:水迷宫定位航行试验染锰组小鼠的逃避潜伏期比对照组小鼠的明显延长(P<0.05),而丰富组小鼠的逃避潜伏期明显比染锰组小鼠的缩短(P<0.05),空间探索实验中,染锰组穿越平台的次数比对照组少,丰富组穿越平台的次数则比染锰组多,贫瘠组比染锰组少,差异有统计学意义(P<0.05)。染锰组和贫瘠组SVZ和SGZ区DCX阳性荧光强度明显比对照组弱,丰富组比染锰组强,差异均有统计学意义。结论:丰富环境可改善锰中毒小鼠的学习记忆能力,其机制可能与促进脑内神经发生有关。

Objective： To investigate the effects of environmental enrichment on learning ＆ memory and the number of newborn neurons of manganese exposed mice. Methods： 40 female Kunming mice （20 ±2 g） of SPF were randomly di- vided into 4 groups： the control group （CG）, standard environment and manganese exposed group （SEG）, enriched en- vironment and manganese exposed group （EEG） , impoverished environment and manganese exposed group （IEG）. The model of manganese exposed mice was prepared by way of intraperitoneal injection of manganese chloride for 3 weeks. The ability of learning and memory was tested by Morris water maze. We use the way of immunofluorescence to label the DCX- positive cells in SVZ and SGZ. Results： In navigation test, compare with CG, the mean latency of SEG was longer signif- icantly （P 〈 0.05） , compare with SEG, the mean latency of EEG was shorter significantly （ P 〈 0.05 ）, but there were no significant difference between IEG with SEG; In the probe test, compared with the SEG, the times of passing through platform of EEG was much more （P 〈 0.05）, and IEG was less significantly （P 〈 0.05 ）. The result of immunofluores- cence showed that the expression of DCX in SVZ and SGZ of IEG and SEG were much lower than that of CG; and expres- sion of DCX in mice of EEG was higher than that of SEG, it is no statistic difference with CG. Conclusion： The ability of learning and memory of manganese exposed mice improved notably by environmental enrichment in which the neurogenesiswas possibly increased by environmental enrichment.