大气颗粒物暴露和高脂高糖饮食对雄性大鼠学习记忆功能的影响

Effects of exposure to atmospheric particulate matters on learning and memory functions in rats fed with high-fat and high-glucose diet

[目的]研究大气颗粒物暴露和高脂高糖饮食对雄性大鼠学习记忆功能的影响。[方法]选择健康3周龄SD雄性大鼠共80只,按照体重随机均分为4组。利用独立通气笼具,暴露组大鼠吸入含大气颗粒物的空气,对照组吸入经过高效过滤器过滤大气颗粒物的空气,对照组和暴露组均设立高脂高糖饮食组和普通饮食组,分别喂饲高脂高糖饮食和普通饮食。每组又分为暴露3个月和暴露6个月2个亚组,每亚组10只大鼠,在暴露后用Morris水迷宫(包括定位航行和空间探索实验)评价各组大鼠的学习记忆能力。[结果]定位航行实验中:暴露3个月,高脂高糖饮食+大气颗粒物暴露组大鼠训练第4天的游泳距离和逃避潜伏期分别为(4.47±1.96)m和(26.89±10.37)s,高于普通饮食对照组的(2.13±1.38)m和(12.99±7.24)s,以及高脂高糖饮食对照组的(2.73±1.09)m和(15.01±4.43)s(P<0.05);暴露6个月,高脂高糖饮食+大气颗粒物暴露组大鼠训练第4天的游泳距离为(7.74±6.64)m,高于普通饮食对照组的(3.68±2.11)m(P<0.05),逃避潜伏期4组间差异无统计学意义(P>0.05)。空间探索实验中:暴露3个月时高脂高糖饮食+大气颗粒物暴露组大鼠的穿越平台次数和目标象限时间分别为(2.30±0.48)次和(31.41±5.48)s,普通饮食+大气颗粒物暴露组的穿越平台次数和目标象限时间分别为(3.30±1.64)次和(31.48±7.85)s,均低于普通饮食对照组[(4.70±1.64)次和(38.95±5.47)s](P<0.05);暴露6个月时高脂高糖饮食+大气颗粒物暴露组大鼠的穿越平台次数[(2.40±1.51)次]低于普通饮食对照组[(4.00±1.05)次](P<0.05)。[结论]大气颗粒物和高脂高糖饮食联合暴露对大鼠学习记忆功能的损伤比单独暴露严重。

[Objective] To explore the effects of exposure to atmospheric particulate matters on learning and memory functions in rats fed with high-fat and high-glucose diet.[Methods] Healthy male SD rats（n=80） aged three weeks were randomized into four groups by weight.The exposure rats were exposed to atmospheric particulate matters in individually ventilated chambers,the control rats inhaled air filtered through highefficiency air filter,and both the control and exposure rats were divided into two groups including a high-fat and high-glucose diet group and a normal diet group.The animals were further divided into a 3-month and a 6-month sub-exposure categories with 10 rats in each subgroup.The abilities of learning and memory of rats were scored by Morris water maze test after the exposures.[Results] In the orientation navigation test,after 3 months of exposure,the swimming distance and escape latency were（4.47±1.96） m and（26.89±10.37） s on training day 4 of the high-fat and high-glucose diet＋atmospheric particulate matters exposure group,higher than those of the normal diet＋filtered air group [（2.13±1.38） m and（12.99±7.24） s] and the high-fat and high-glucose diet＋filtered air group [（2.73±1.09） m and（15.01±4.43） s]（P〈0.05）;after 6 months of exposure,the swimming distance was（7.74±6.64） m on training day 4 of the high-fat and high-glucose diet＋atmospheric particulate matters group,higher than that of the normal diet＋filtered air group [（3.68±2.11） m]（P〈0.05）,and no difference in escape latency was found among the four groups（P〉 0.05）.In the spatial probe test,after the 3-month exposure,the count of traversing platform and target quadrant time were（2.30±0.48） and（31.41±5.48） s in the rats co-exposed to high-fat and high-glucose diet and atmospheric particulate matters,and（3.30±1.64） and（31.48±7.85） s in the rats treated with normal diet and atmospheric particulate matters;the two parameters in the two groups were lower than those of the normal diet＋filtered air group [（4.70±1.64） and（38.95±5.47） s]（P〈0.05）.The count of traversing platform of the rats co-exposed to high-fat and high-glucose diet and atmospheric particulate matters（2.40±1.51） was lower than that of the normal diet＋filtered air group（4.00±1.05） after the 6-month exposure（P〈0.05）.[Conclusion] Combined exposure to atmospheric particulate matters and high-fat and high-glucose diet could induce more severe impairments in the learning and memory function of rats than single exposure.