14C-苯并(a)芘在大鼠海马中的分布及对海马神经元的损害
Dynamic Distribution of 14C-benzo(a)pyrene and Damage of Neuron in Hippocampus of Rat
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摘要:
目的 观察苯并(a)芘B(a)P在大鼠海马中的分布及对其神经元的损害。 方法 将150只SD大鼠随机分为对照组和实验组,实验组尾静脉注射14C-B(a)P 3.7& #215;105 Bq/kg,对照组注射相同剂量的生理盐水。在染毒后1、6、12、24、48 h,用光镜自显影法观察14C-B(a)P在大鼠脑组织中的分布,HE染色光镜和电镜观察14C-B(a)P对大鼠海马CA1区神经元的损害。 结论 光镜放射自显影观察表明,在海马组织中的14C-B(a)P银粒数随染毒后时间的延长而逐渐增加,24 h达到高峰,48 h明显减少,1、6、12、24、48 h银粒数分别为(22.31& #177;2.11)、(23.11& #177;2.32)、(25.97& #177;2.97)、(28.16& #177;3.17)、(17.16& #177;1.85)粒/mm3,差异具有统计学意义(F=28.65,P<0.01)。HE染色光镜观察发现:染毒后12 h海马神经元细胞排列稀疏、数量减少,核变小、部分出现固缩现象,随着时间的推移,损害逐渐加重。电镜观察发现:大鼠海马神经元及细胞器在染毒后不同时间点有不同程度的损害,主要表现为海马神经纤维水肿,脱髓鞘样改变、线粒体肿胀、高尔基复合体扩张、核膜部分溶解,突触前膜致密斑明显。 结论 14C-B(a)P在海马组织中的分布随时间的增加而增加,24 h达到高峰;不同时间点B(a)P对海马神经元有不同程度的损害。 Abstract:Objective To observe dynamic distribution of 14C-benzo (a) pyrene14C-B(a)Pand the related damage of neuron in hippocampus of rat. Methods A total of 150 Sprague Dawley rats were divided into control group and experimental group. The rats in the experimental group were given a single intravenous injection of 3.7& #215;105 Bq/kg of 14C-B(a)P while the same doses of normal saline were given to the control group. The rats were sacrificed at 1, 6, 12, 24 and 48 hours after the administration of radiolabelled 14C-B(a)P. Light microscopic autoradiography were used to observe the dynamic distribution of 14C-B(a)P in hippocampus tissue. The morphosis of neuron in the hippocampus of rats was observed by hematoxylin and eosin (HE)staining and a transmission electron microscopy. Results The silver granules in the hippocampus of rats increased along with time, which reached the peak in 24h and sharply decreased in 48h. The silver grain counts were (22.31& #177;2.11)(, 23.11& #177;2.32)(, 25.97& #177;2.97), (28.16& #177;3.17)and (17.16& #177;1.85)grains/mm3 at 1, 6, 12, 24 and 48 hours after the administration of radiolabelled 14C-B(a)P, the difference was significant (F=28.65, P<0.01). The nucleus of neurons arranged in sparse and became smaller, and the number was also reducing, portion condensation phenomenon was recorded after 12 hours exposure to HE stain. The damage gradually in creased over time. Under transmission electron microscope, the damages of hippocampal neurons and organelles were varied at different time points after exposure, such as hippocampal nerve fiber edema, demyelination, swelling of mitochondria, golgi complex expansion, partial dissolution of the nuclear membrane and dense patches of presynaptic membrane. Conclusion The silver granules in the hippocampus of rats increased along with time which reached the peak in 24 h. The damages of hippocampal neurons and organelles were varied at different time points.
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