目的 观察党参多糖对铅中毒小鼠学习记忆的影响及其作用机制。方法 利用Morris水迷宫及跳台试验观察铅中毒小鼠学习记忆能力,亚硝酸盐法测定脑组织超氧化物歧化酶(superoxide dismutase ,SOD)活力,硫代巴比妥酸比色法测定丙二醛(monochrome display adapter ,MDA)含量,双硝基苯甲酸法测定小鼠脑组织乙酰胆碱酯酶(acetylcholine acetylhydrolase,AChE)含量。结果 Morris水迷宫试验结果表明,到达平台时间党参多糖中、高剂量组较模型组显著缩短(P＜0.05),穿越平台次数较模型组显著增加(P＜0.05)。跳台试验结果表明,与模型组比较,党参多糖中、高剂量组在学习训练及记忆测试中跳下平台的触电潜伏期显著延长(P＜0.05),错误次数显著降低(P＜0.05),触电时间明显下降(P＜0.01)。党参多糖中、高剂量组与模型组比较,脑组织SOD活性升高,MDA含量降低,AchE含量无统计学差异。结论 党参多糖能改善铅中毒小鼠的学习记忆能力,其机制可能与改善脑内脂质过氧化,清除自由基有关。

Objective To study the effect of polysaccharides from Radix codonopsis ( PRC ) on memory disorder of lead poisoning mice and to explore its mechanism. Methods The learning ability of lead poisoning mice were detected by Morris water maze and step-down test, the activity of super oxide dismutases ( SOD ) in brain was determined by the nitrite formation and the content of malondialdehyde ( MDA ) in brain was determined by thiobarbituric acid colorimetric method,nitrobenzoic acid method was used to detect the content of acetylcholine esterase ( AchE ). Results During Morris water maze test ,compared with model group, in the middle and high dose of PRC groups mice, the latent period to reach the platform was significantly reduced (P<0.05) and the time to across the plat was significantly increased (P<0.05) . In step-down test, compared with model group , the learning training and memory test was significantly prolonged (P<0.01), the mistakes were significantly decreased (P<0.05), and electrifying time was significantly lowered (P<0.01). The activities of SOD were decreased and the content of MDA was increased in brain tissue of lead poisoning mice in the middle and high dose of PRC groups (P<0.05).There was no significant difference in AchE content. Conclusions PRC enhances the ability of learning and memory in lead poisoning mice. The mechanism may in improving lipid peroxidation and free radical scavenging.Further study of AchE content in brain in brain tissue of lead poisoning mice is needed.