苯并[a]芘对大鼠海马神经元形态学的影响

目的研究苯并[a]芘(B[a]P)对大鼠海马形态学和突触的影响。方法初断乳雄性Wistar大鼠40只,随机分为空白对照组、溶剂对照组和3个染毒组(分别为6.25、2.5和1mg/kg体重),连续腹腔染毒13周(90d)。在染毒结束后,用电镜和光镜观察海马形态学改变。结果 HE染色对照组和B[a]P暴露各组大鼠海马神经元形态结构未见明显异常,电镜仅高剂量组偶有线粒体肿胀和核浓缩现象出现。高剂量组神经元突触PSD厚度和突触活性区长度均明显小于对照组和低剂量组(P﹤0.05),突触界面半径明显大于对照组和低剂量组(P﹤0.05)。结论低剂量B[a]P暴露对海马神经元形态和超微结构无明显影响,但B[a]P可能引起突触形态学的改变,降低突触的传递效率,因而影响学习记忆能力。

Effects of benz[a]pyrene on hippocampus morphology of rats

OBJECTIVE To study the effects of benz[a]pyrene on the hippocampus morphology of rats.METHODS Forty Wistar growing rats were randomly divided into five groups:blank control group,rats in solvent group were injected vegetable oil and those in experimental groups were peritoneal injected different doses of B(a)P(1mg/kg,2.5mg/kg,6.25mg/kg)every day for 13 weeks.After 90 d,the hippocampus morphology of rats was observed by haematine-eos in staining and the ultrastructure of hippocampus by the transmission electron microscopy.RESULTS Results of pathological sections stained with hematoxylin and eosin showed that hippocampal neurons from all groups exhibited a typical normal appearance.Electron micrographs confirmed the normal appearance of hippocampal neurons,except a few swelled mitochondrias appearing in 6.25 mg/kg treatment group.Hippocampal synapse morphology was observed by transmission electron microscopy.The length of postsynaptic dlensity(PSD)and length of active zone were significantly shorter than those of control groups(P﹤0.05),and radius of modeling circular of synaptic interface was significantly larger than those of controls(P﹤0.05).CONCLUSION The study suggests that low dose of B[a]P dose not impair the morphology and structure of hippocampal neuron,but B[a]P may change the hippocampal synapse morphology,further leading to impair the capability of learning and memory in rats.