降铅冲剂对低水平铅暴露鼠脑一氧化氮合酶及学习记忆的影响

Effects of Granule taken from lead on nitric oxide synthase and ability of learning and memory in brains of rats exposed to low level lead.

[目的]采用学习记忆行为指标、不同脑区的一氧化氮合酶（NOS）活性的改变,为全面的评价中药降铅冲剂的疗效,及对神经系统损伤的保护作用提供依据.[方法]选用Wistar大鼠仔鼠60只,体重80～100 g,随机分成6组,每组10只,分别为空白组、模型对照组、EDTA对照组、降铅冲剂低剂量组、降铅冲剂中剂量组、降铅冲剂高剂量组;造膜后开始给药,EDTA对照组给CaNa2EDTA注射液10mg/（kg·d）腹腔注射,降铅冲剂低、中、高三组分别予降铅冲剂5、10、20 g/（kg·d）的剂量灌胃,空白组和模型对照组予等量的蒸馏水灌胃,给药共30 d.利用Y迷宫观察降铅冲剂对铅中毒大鼠学习记忆能力的影响;以不同脑区NOS活性作为评价降铅冲剂的神经生化指标.[结果]①染铅后,Y迷宫实验表明铅接触组大鼠的分辨学习和记忆能力均比空白组显著下降（P＜0.01）,经过30 d治疗后,降铅冲剂各组的记忆保持率明显高于模型对照组,效果优于EDTA;②染铅后,大脑皮层和小脑区的NOS活性显著降低,而海马区活性亦有降低趋势,治疗后,降铅冲剂各组不同脑区的NOS都有不同程度增加.[结论]从生化角度说明降铅冲剂能改善铅致学习记忆的损害.

[Objectives] To provide basis for evaluating curative effect of Granule taken from lead and the role of it in the protection against injuries to nervous system, with ability of learning and memory and the changes of NOS activity in different brain regions. [Methods] 60 Wister rats （80-100 g） were divided into 6 groups （n= 10 each） randomly. After models of rats exposed to low level lead were established,one group of rats were treated with CaNa2EDTA 10 mg/（kg· d） for 30 days Three groups were lavaged with high, medium, low dose of Granule taken from lead 5,10,20 g/（kg· d）. The last two groups were lavaged with equal distilled. Effects of Granule taken from lead on ability of learning and memory were observed with Y maze and that on nervous biochemistry were evaluated with NOS activity in different brain regions. [Results] ①Y maze test indicated that the ability of learning and memory in brains of rats exposed to low level lead was significantly lower than that of normal rats （P〈0. 01 ）. The retain percent of learning and memory of the three groups treated by Granule taken from lead was obviously increased, which was higher than that of positive control group and EDTA group. ②NOS activity in cerebral cortical and cerebellums was obviously decreased and that in hippocampus had tendency of descent in brains of rats exposed to low level lead. NOS activity in different brain regions of rats treated by Granule taken from lead was increased in different degree. [Conclusion] It indicated that Granule taken from lead can amend the impairment of learning and memory in rats exposed to low level lead.