论文部分内容阅读
目的探讨纳米氧化铝吸入暴露染毒对小鼠神经行为学的持续影响及其可能存在的机制。方法将40只健康ICR小鼠随机分成4组,每组10只,1组为对照组,3组为纳米氧化铝暴露染毒。应用动式吸入染毒柜,同时给予各暴露染毒组小鼠纳米氧化铝动态吸入染毒,染毒浓度1 mg/m3,每天暴露8 h,连续染毒14 d,于染毒开始前1 d(对照组),染毒结束后1 d(暴露后1 d组)、60 d(暴露后60 d组)、90 d(暴露后90 d组),采用旷场试验和Morris水迷宫试验检测小鼠的空间学习和记忆能力,取大脑皮层组织作苏木素-伊红(HE)染色和淀粉样蛋白前体(amyloid precursor protein,APP)免疫组化染色,qRT-PCR检测APP mRNA的表达水平,并用试剂盒法检测脑组织中腺嘌呤核苷三磷酸(ATP)、丙二醛(MDA)、活性氧(ROS)含量。结果旷场试验中,与对照组相比,除暴露后1 d组小鼠在进入中心区频率差异无统计学意义,其余各组小鼠各项指标均降低且差异有统计学意义(P<0.05);水迷宫试验中,各暴露染毒组小鼠平台象限停留时间均降低,差异均有统计学意义(P<0.05);穿越平台区频率均降低,仅暴露后90 d组小鼠差异有统计学意义(P<0.05)。大脑皮层的HE染色均未见明显的病理改变,APP免疫组化染色显示暴露后90 d组APP阳性细胞明显增加;qRT-PCR检测显示,APP mRNA的表达水平随暴露后天数增加而升高,且差异均有统计学意义(P<0.05);脑组织中ATP水平与对照组相比均降低,暴露后60和90 d组小鼠ATP水平差异有统计学意义(P<0.05),MDA含量和ROS含量均升高且差异均有统计学意义(P<0.05)。结论经纳米氧化铝暴露染毒,脱离暴露环境后,仍然会提高小鼠脑组织氧化应激水平并改变其神经行为学。APP的过度表达以及脑组织氧化应激反应可能是纳米氧化铝导致小鼠神经行为学改变的重要机制之一。
Objective To investigate the sustained effect of nano-alumina inhalation exposure on neurobehavioral and its possible mechanism. Methods Forty healthy ICR mice were randomly divided into 4 groups with 10 mice in each group. One group was control group, and the other three groups were exposed to nano-alumina exposure. Application of dynamic inhalation cabinets, while exposed to exposed mice exposed to nano-alumina dynamic inhalation exposure, exposure concentration 1 mg / m3, daily exposure to 8 h, continuous exposure to 14 d, before the start of exposure 1 d (control group), 1 d after exposure (1 d after exposure), 60 d (60 d after exposure), 90 d (90 d after exposure), and open field test and Morris water maze test The spatial learning and memory ability of mice was evaluated by immunohistochemical staining of hematoxylin-eosin (HE) and amyloid precursor protein (APP) in cerebral cortex. The expression of APP mRNA was detected by qRT-PCR. The contents of adenosine triphosphate (ATP), malondialdehyde (MDA) and reactive oxygen species (ROS) in brain tissue were detected by kit method. Results In the open-field test, compared with the control group, there was no significant difference in the frequency of entering the central area between the 1st day and the 3rd day after exposure, while the rest of the mice in each group were decreased and the difference was statistically significant (P < 0.05). In the water maze test, the dwell time in the quadrant of each exposed exposure group was significantly lower than that in the control group (P <0.05) There was statistical significance (P <0.05). There was no obvious pathological changes in cerebral cortex HE staining, APP immunohistochemical staining showed 90 days after exposure APP positive cells increased significantly; qRT-PCR test showed that APP mRNA expression increased with the days after exposure increased, (P <0.05). Compared with the control group, the levels of ATP in the brain tissue decreased significantly. The levels of ATP in the mice at 60 and 90 d after exposure were significantly different (P <0.05) And ROS levels were increased and the differences were statistically significant (P <0.05). Conclusion Exposure to nano-alumina exposure and exposure to the environment will still increase the level of oxidative stress in brain tissue of mice and alter their neurobehavioral characteristics. Overexpression of APP and oxidative stress in brain tissue may be one of the important mechanisms by which nano-alumina causes neurobehavioral changes in mice.