铅暴露对快速衰老小鼠学习记忆能力的影响

发布时间：2018-11-27 14:10

【摘要】：[目的]探讨铅(Pb)暴露对快速衰老小鼠(SAMP8)学习记忆能力的影响及其机制。[方法]雄性SAMP8小鼠及其野生型SAMR1小鼠各20只,各随机分为2组,即SAMR1组、SAMR1+Pb组和SAMP8组、SAMP8+Pb组。SAMR1+Pb组和SAMP8+Pb组小鼠每天饲以0.05 g/L醋酸铅饮用水,SAMR1组和SAMP8组小鼠每天饲以0.05 g/L醋酸钠饮用水,共饮水9周。应用Morris水迷宫实验检测小鼠学习记忆能力;采用免疫荧光法测定实验小鼠侧脑室下区(SVZ)淀粉样前体蛋白(APP)、神经元母细胞和星形胶质样细胞特异性标志物[双皮质素(DCX)、神经胶质纤维酸性蛋白(GFAP)]的表达情况,分析神经元母细胞和星形胶质细胞的细胞比率变化;应用实时荧光定量PCR检测实验小鼠SVZ中DCX、GFAP和脑源性神经营养因子(BDNF)的m RNA表达情况。[结果]小鼠Morris水迷宫实验第3天结果显示:与SAMR1组[(10.94±3.98)s]相比,SAMP8组[(29.24±6.15)s]、SAMR1+Pb组[(34.15±6.78)s]和SAMP8+Pb组[(50.86±8.56)s]的逃避潜伏期延长,差异有统计学意义(P0.05);且与SAMP8组和SAMR1+Pb组小鼠比较,SAMP8+Pb组小鼠的逃避潜伏期更长(P0.05)。SAMR1组、SAMP8组、SAMR1+Pb组和SAMP8+Pb组小鼠的平均穿越平台次数分别为(6.75±1.28)、(3.25±1.28)、(3.88±1.46)、(1.25±0.46)次;SAMP8组、SAMR1+Pb组和SAMP8+Pb组小鼠穿越次数较SAMR1组均减少(P0.05);SAMP8+Pb组小鼠穿越次数也明显低于SAMP8组和SAMR1+Pb组(P0.05)。免疫荧光法测定结果显示:与SAMR1组小鼠比较,SAMR1+Pb组、SAMP8组和SAMP8+Pb组小鼠SVZ区APP荧光强度分别上升了79%、53%和216%;与SAMR1+Pb组和SAMP8组比较,SAMP8+Pb组小鼠APP荧光强度分别上升了76%和107%,差异均具有统计学意义(P0.05)。与SAMR1组小鼠比较,SAMP8组和SAMP8+Pb组小鼠SVZ中GFAP(+)/DAPI(+)和DCX(+)/DAPI(+)细胞比率均降低,SAMP8+Pb组小鼠SVZ的GFAP(+)/DAPI(+)和DCX(+)/DAPI(+)细胞比率分别为SAMP8组小鼠的22%和59%。实时荧光定量PCR分析结果显示:与SAMR1组小鼠相比,SAMR1+Pb组、SAMP8组和SAMP8+Pb组小鼠SVZ中BDNF和DCX m RNA表达明显下降(P0.05);SAMP8+Pb组小鼠BDNF m RNA表达较SAMR1+Pb组和SAMP8组小鼠分别下降了85%和83%,DCX mR NA表达则分别下降了81%和60%,差异有统计学意义(P0.05);SAMP8组和SAMP8+Pb组小鼠的GFAP m RNA表达较SAMR1组明显下降,并且SAMP8+Pb组小鼠GFAP m RNA表达较SAMR1+Pb组和SAMP8组分别下降了89%和69%,差异有统计学意义(P0.05)。[结论]铅暴露可导致快速衰老小鼠SVZ中APP表达增加和BDNF m RNA表达下降,同时加剧SVZ中星形胶质样细胞丢失,逃避潜伏期延长,穿台次数下降,提示铅暴露加剧快速衰老小鼠学习记忆能力的下降。
[Abstract]:[objective] to investigate the effect of lead (Pb) exposure on learning and memory ability of rapid aging mice (SAMP8) and its mechanism. [methods] Twenty male SAMP8 mice and their wild-type SAMR1 mice were randomly divided into two groups: SAMR1 group, SAMR1 Pb group and SAMP8 group, SAMP8 Pb group, SAMR1 Pb group and SAMP8 Pb group. Mice in SAMR1 group and SAMP8 group were fed with 0.05 g / L sodium acetate drinking water daily for 9 weeks. Morris water maze test was used to detect the ability of learning and memory in mice. Detection of specific markers of (SVZ) amyloid precursor protein (APP),) neuron mother cells and astrocytes in subventricular region of mice by immunofluorescence assay The expression of glial fibrillary acidic protein (GFAP) and the ratio of neuron mother cells and astrocytes were analyzed. The expression of DCX,GFAP and brain-derived neurotrophic factor (BDNF) m RNA in SVZ of experimental mice was detected by real-time fluorescence quantitative PCR. [results] on the 3rd day of Morris water maze test in mice, the results showed that compared with SAMR1 group [(10.94 卤3.98) s], SAMP8 group [(29.24 卤6.15) s], The escape latency of SAMR1 Pb group [(34.15 卤6.78) s] and SAMP8 Pb group [(50.86 卤8.56) s] was prolonged (P0.05). The escape latency of SAMP8 Pb group was longer than that of SAMP8 group and SAMR1 Pb group (P0.05). The average crossing times of SAMR1 group, SAMP8 group, SAMR1 Pb group and SAMP8 Pb group were (6.75 卤1.28), (3.25 卤1.28, respectively. (3. 88 卤1. 46), (1. 25 卤0. 46) times; The crossing times of SAMP8 group, SAMR1 Pb group and SAMP8 Pb group were significantly lower than those of SAMR1 group (P0.05), and that of SAMP8 Pb group was significantly lower than that of SAMP8 group and SAMR1 Pb group (P0.05). Compared with SAMR1 group, the fluorescence intensity of APP in SVZ region of SAMR1 Pb group, SAMP8 group and SAMP8 Pb group increased by 79% and 216%, respectively. Compared with SAMR1 Pb group and SAMP8 group, the fluorescence intensity of APP in SAMP8 Pb group increased by 76% and 107%, respectively, and the difference was statistically significant (P0.05). Compared with SAMR1 group, the ratio of GFAP () / DAPI () and DCX () / DAPI () cells in SVZ of SAMP8 group and SAMP8 Pb group decreased. The GFAP () / DAPI () and DCX () / DAPI () ratios of SVZ in SAMP8 Pb group were 22% and 59% of those in SAMP8 group, respectively. The results of real-time fluorescence quantitative PCR analysis showed that the expression of BDNF and DCX m RNA in SVZ of SAMR1 Pb group, SAMP8 group and SAMP8 Pb group was significantly lower than that of SAMR1 group (P0.05). Compared with SAMR1 Pb group and SAMP8 group, the expression of BDNF m RNA in SAMP8 Pb group decreased by 85% and 83%, and decreased by 81% and 60%, respectively (P0.05). The expression of GFAP m RNA in SAMP8 group and SAMP8 Pb group was significantly lower than that in SAMR1 group, and the GFAP m RNA expression in SAMP8 Pb group was 89% and 69% lower than that in SAMR1 Pb group and SAMP8 group, respectively. The difference was statistically significant (P0.05). [conclusion] lead exposure can increase the expression of APP and decrease the expression of BDNF m RNA in SVZ of rapidly aging mice, and aggravate the loss of astrocytes in SVZ, prolong the escape latency and decrease the number of platform penetration. It suggested that lead exposure aggravated the decline of learning and memory ability in rapidly aging mice.
【作者单位】：华北理工大学公共卫生学院;华北理工大学医学实验动物中心;
【基金】：国家自然科学基金项目(编号:81373033,81673208)
【分类号】：R114

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