孕期暴露纳米氧化铝对子代小鼠神经发育的影响

Effects of maternal exposure to nano-alumina during pregnancy on neurodevelopment in offspring mice

目的 观察小鼠孕期暴露纳米氧化铝对子代神经发育的影响.方法 ICR雌性小鼠于交配前10d开始染毒至仔鼠出生.所有雌鼠随机分为5组：溶剂对照组（生理盐水）、纳米碳组（11.76mg/ml）、微米氧化铝组（50 mg/ml）、50 nm氧化铝组（50 mg/ml）、13 nm氧化铝组（50 mg/ml）.均采用滴鼻方式以10 μl/次,3次/d,染毒至仔鼠出生,采用生理学指标、反射和感觉功能试验、耐力实验、Morris水迷宫、定位导航、旷场实验等方法检测仔鼠的神经发育情况.结果 出生后28 d,13 nm粒径氧化铝染毒组体重[（16.73±4.04）g]明显低于溶剂对照组[（20.45±2.50）g],差异有统计学意义（P＜0.01）；与溶剂对照组[（4.45±0.50）d]相比,13 nm氧化铝组张耳天数[（4.91±0.78）d]延迟,差异有统计学意义（P＜0.01）,与溶剂对照组出牙天数[（10.05±0.23）d]比,其他各组出牙指标都出现延迟,其中纳米碳组[（10.32±0.48）d]、微米粒径铝组[（10.75±0.45）d]、50 nm粒径氧化铝组[（10.32±0.47）d]、13 nm粒径氧化铝组[（10.79±0.49）d],差异有统计学意义（P＜0.05,P＜0.01）.反射和感觉功能方面：在出生后第4天和第7天测试的悬崖回避实验中,与溶剂对照组相比其余各组悬崖回避达标率均有不同程度的降低（P＜0.05,P＜0.01）.耐力测试方面：在出生后12d和14 d测试的相对于溶剂对照组,纳米碳组、50 nm粒径氧化铝组、13 nm氧化铝组仔鼠前置悬挂时间减少,差异有统计学意义（P＜0.05,P＜0.01）.Morris水迷宫、定位导航试验：在定位导航试验中,13 nm粒径氧化铝组连续5d潜伏期与溶剂对照组比较有增加,差异有统计学意义（P＜0.05）；穿越平台的次数方面与溶剂对照组相比,其他组穿越次数减少,差异有统计学意义（P＜0.05,P＜0.01）.旷场实验方面：与溶剂对照组相比,纳米碳组与13 nm粒径氧化铝组的站立次数减少（P＜0.05）,与溶剂对照组相比较其他各组的修饰次数均减少（P＜0.01）.结论 孕期暴露13 nm粒径氧化铝会对仔鼠的生理发育、早期行为发育产生抑制作用；对子代大脑学习记忆能力,及其对新异环境的适应能力产生抑制；在耐力实验、直立次数方面随着纳米氧化铝粒径的减小其对仔鼠的发育毒性增大.

Objective To observe the effects of maternal exposure to nano-alumina during pregnancy on the neurodevelopment in offspring mice.Methods Female ICR mice began to be exposed to nano-alumina 10 d before mating,and the nano-alumina exposure lasted till offspring mice were born.All the female mice were randomly divided into 5 groups：solvent control group （saline）,nano-carbon group （11.76 mg/ml）,microalumina group （50 mg/ml）,50 nm alumina group （50 mg/ml）,and 13 nm alumina group （50 mg/ml）.All the mice were treated by nasal drip （10 μl/time） 3 times daily till offspring mice were born.Physiological indices,reflex and sensory function test,endurance test,Morris water maze test,positioning and navigation test,and open field test were used to evaluate the neurodevelopment of newborn mice.Results On day 28,the body weight of 13 nm alumina group （16.73±4.04 g） was significantly lower than that of solvent control group （20.45±2.50 g）（P＜0.01）; the 13 nm alumina group had significantly delayed time to ear opening compared with the solvent control group （4.91±0.78 d vs 4.45±0.50 d,P＜0.01）; compared with the solvent control group,the nano-carbon group,micro-alumina group,50 nm alumina group,and 13 nm alumina group had significantly delayed time to eruption of teeth （10.05±0.23 d vs 10.32±0.48 d,10.75±0.45 d,10.32±0.47 d,and 10.79±0.49 d,P＜0.05 or P＜0.01）.On days 4 and 7 after birth,compared with the solvent control group,other groups had significantly decreased proportions of mice which passed the cliff avoidance test （P＜0.05 or P＜0.01）.On days 12 and 14 after birth,compared with the solvent control group,the nano-carbon group,50 nm alumina group,and 13 nm alumina group had significantly reduced pre-suspension time in the endurance test （P＜0.05 or P＜0.01）.The Morris water maze and positioning and navigation tests showed that the 13 nm alumina group had a significantly increased 5 d incubation period compared with the solvent control group （P＜0.05）; compared with the solvent control group,other groups had significantly reduced numbers of platform crossings （P＜0.05 or P＜0.01）.The open field test showed that the nano-carbon group and 13 nm alumina group had reduced numbers of rearings compared with the solvent control group （P＜0.05）; compared with the solvent control group,other groups had significantly reduced numbers of modifications （P＜0.01）.Conclusion Maternal exposure to nano-alumina （13 nm） during pregnancy has inhibitory effects on the physical development and early behavioral development in newborn mice and can also inhibit the learning and memory abilities and adaptability to new environment in offspring mice.The neurodevelopmental toxicity of nano-alumina to newborn mice increases as the particle sizes of nano-alumina decrease,which has been demonstrated by the endurance test and number of rearings.