侧脑室注射苯并(a)芘致大鼠脑组织形态学及行为学的改变

Study on Morphology in Rat Brain Tissue and Behavioral Change by Intracerebroventricular Injecting Benzo(a)pyrene

[目的]研究侧脑室注射苯并(a)芘[B(a)P]致大鼠脑组织形态学及行为学的改变。[方法]32只SD大鼠随机分为4组,每组8只,染毒组分为高、中、低3个剂量组(31.5、63.1、126.2μg/kg体重),并设橄榄油溶剂对照组。采用侧脑室微量注射染毒处理,每周1次,连续3周;对照组用橄榄油溶剂作平行处理。记录一般情况及神经系统表现;实验第6周末采用跳台实验法测大鼠的学习记忆成绩,并取各组大鼠脑组织大脑皮质、海马、小脑作病理切片观察组织损伤的形态学指标。[结果]与对照组相比,低剂量组潜伏期缩短(P<0.05);中剂量组学习期和记忆期的错误次数即EN1和EN2均增加(P<0.01)、潜伏期缩短(P<0.05);高剂量组EN1增加(P<0.01)、EN2增加(P<0.05)、潜伏期缩短(P<0.01);染毒组在光镜下可见到组织损伤的形态学改变,高剂量组各组织在光镜下可见较为集中的坏死区,而对照组的组织结构未见异常。[结论]病理形态学指标及跳台实验结果显示B(a)P具有神经毒性,可损伤大鼠脑组织并引起神经行为的改变。

[ Objective ] To stduy the morphology in rat brain tissue and behavioral changes by intracerebroventricular injecting Benzo （ a ） pyrene. [ Methods ] 32 SD rats were divided into 4 groups at random, i.e.3 exposed groups and a vehicle control group. The exposed groups were treated by lateral cerebral ventricle micro-injection with B （ a ） P dissolved in olive oil at 31.5, 63.1 and 126.2 mg/kg respectively, once every week for 3 weeks, the vehicle control group was treated with olive oil. The general conditions and signs of neurotoxicity on the animals were observed and recorded. The step-down test was performed to test the learning and memory abilities in rats. After the experiment, Specimens of the cerebral cortex, hippocampus and cerebellum were sliced and their morphological changes were observed under optical microscope. [ Results ] From the behavioral experiment, it showed that compared with the olive oil group, the latency（ LT ）was shortened（ P 〈 0.05 ）in the low-dose group; both error numbers（ EN1 ）and（ EN2 ）decreased significantly（ P 〈 0.01 ）and the LT shortened（ P 〈 0.05 ）in the medium-dose group; whereas EN1 and EN2 increased significantly（ P 〈 0.01, P 〈 0.05 respectively ）and the LT shortened obviously（ P 〈 0.01 ）in the high-dose group. In B（ a ）P exposed groups, morphological observations showed tissue injury under microscopy. There Were focal necrosis areas in the high-dose group and no significant damage could be. seen in the vehicle control group. [ Conclusion ] From the morphological changes and behavioral experiment, it showed that B（ a ）P is a neurotoxin. It could damage the rat brain tissue as well as induce the neurobehavioral change.