侧脑室注射苯并[a]芘对大鼠脑组织病理学改变和学习记忆的影响

Lateral ventricle injection of benzene[a]pyrene in histopathological rats change and the influence of learning and memory

目的研究侧脑室注射苯并(a)芘(B[a]P)对大鼠学习记忆的影响及脑组织病理学的变化。方法分别以0.9%氯化钠注射液、5.0mmol/L B[a]P、10.0mmol/L B[a]P无菌溶液10μL给大鼠侧脑室注射染毒,于染毒结束8d后用Morris水迷宫、跳台和避暗试验等测定大鼠的学习记忆能力。处死后用苏木精-伊红(HE)染色观察大脑皮质和海马CA1区病理组织学的变化。结果染B[a]P组大鼠跳台、避暗实验潜伏期和空间探索试验中目标象限停滞时间较对照组显著缩短(P<0.05),错误次数显著增多(P<0.05),且有剂量反应关系,表明B[a]P可导致大鼠神经行为发生改变,学习记忆障碍。随着染B[a]P剂量增加,大鼠皮质和海马CA1区细胞连接松解,排列逐渐零乱,有环状带出现,细胞数目减少,细胞核、胞体变小。表明随着染B[a]P剂量的增加,大鼠皮质和海马CA1区神经细胞形态结构改变越明显。结论 B[a]P可致大鼠学习记忆发生障碍,且随染B[a]P剂量增加对大鼠造成的损伤越大,可为B[a]P神经毒性的研究提供良好的实验基础。

Objective To study the effect of the lateral ventricle injection of benzene and （a） pyrene （B[a] P） on the learning and memory of rats and the pathological changes of the brain tissue. Methods Ten μL of 0. 9 physiological saline injection, 5.0 and 10.0 mmol/LB[a]P were injected into the rats respectively. After 8 days exposure, the rats were tested on their learning and memory ability with Morris water maze, step-down and stepthrough test. HE staining was used to observe the histopathological changes in the cerebral cortex and bippoeampus CA1 area after execution. Results In group B[a]P, latent period of step-down passive avoidance test and target quadrant dwelling time of spatial exploration were significantly shorter than the control group （ P d0.05） ; error frequency significantly increased （ P d0.05）, and there was a dose-dependent relationship, which indicated that B[a] could lead to the changes of neural behavior, dysfunction of learning and memory in rats. With the dose increased, the connection released in rat cortex and hippocampus CA1 cell, the arrangement became disordered, annular bands appeared and the number of cells reduced, while the nuclei and cell body became smaller. It showed that the morphological and structural changes of neurons in CA1 area of rat cortex and hippocampus were more obvious with the dose increase of B[a]P. Conclusion B[a]P can cause learning and memory impairment in rats. And with the increase of the B[a]P dose, the damage caused by the [a]P was worse. It maybe provide a good experimental basis for the study of neurotoxicity of B[a]P.