枸杞多糖对染铅小鼠学习记忆的影响

Effect of lycium barbarum polysaccharides on the learning and memory of lead-exposed mice

目的:探讨染铅小鼠灌服枸杞多糖后学习记忆的变化。方法:实验于2004-02/05在暨南大学药学院实验技术中心完成。选择健康6周龄昆明种小鼠50只,分为5组,即空白对照组,染铅模型组及枸杞多糖3.6g/kg,1.8g/kg,0.9g/kg组,每组10只。将醋酸铅溶于蒸馏水中按40mg/kg腹腔注射于染铅模型组及枸杞多糖组。枸杞多糖3个剂量组分别灌胃3.6,1.8,及0.9g/kg的枸杞多糖,其余两组灌服等量生理盐水,连续给药6周。第7周采用Morris水迷宫(RB-100B圆型水迷宫)实验观察动物学习记忆变化情况,以连续8次训练中7次未超过15s找到避难台为训练达标。于训练1h后和1周后分别进行5次测试,记录每次到达避难台所需时间。第8周取小鼠血和股骨测血铅和骨铅含量。结果:50只小鼠全部进入结果分析。①小鼠血铅含量:模型对照组显著高于空白对照组(1.70±0.01)mg/kg,(0.06±0.01)mg/kg,(t=366.7,P<0.01)。枸杞多糖1.8g/kg,,3.6g/kg组显著低于模型对照组(0.30±0.23)mg/kg,(0.09±0.15)mg/kg,(t=19.32,33.87,P<0.05)。②小鼠骨铅含量:模型对照组显著高于空白对照组(175.7±28.9)mg/kg,(1.4±0.9)mg/kg,(t=19.06,P<0.01)。枸杞多糖0.9g/kg,1.8g/kg,3.6g/kg组均显著低于模型对照组(153.5±29.3)mg/kg,(132.9±28.5)mg/kg,(122.8±19.6)mg/kg,(t=1.71～3.33,P<0.05)。③小鼠到避难台的时间:枸杞多糖不同剂量组均较模型对照组缩短,其中3.6g/kg组小鼠1h后到避难台的时间显著短于模型对照组(28.2±13.6)s,(39.1±18.2)s,(t=1.80,P<0.05)。结论:枸杞多糖能有效促进染铅小鼠体内铅排除,改善铅对小鼠学习记忆的损害作用。可推测其改善记忆作用与枸杞多糖降低小鼠体内铅含量有关。

AIM： To investigate the learning and memory changes of lead-exposed mice after perfusion of Lycium barbarum polysaccharides. METHODS： The experiment was carried out in the Center of Experimental Technique, School of Pharmacology, Jinan University, Guangzhou 510632, Guangdong Province, China between February and May 2005. Fifty healthy 6-week-old Kunming mice were divided into 5 groups with 10 rats in each group： blank control group, lead-exposed model group and Lycium barbarum polysaccharides 3.6, 1.8 and 0.9 g/kg groups. Lead acetete was dissolved in the distilled water, and then injected intraperitoneally （40 mg/kg） into the mice in the lead-exposed model group and Lycium barbarum polysaccharides groups. The mice in the 3 Lycium barbarum polysaccharides groups were treated with Lycium barbarum polysaccharides of 3.6, 1.8 and 0.9 g/kg respectively, and those in the other 2 groups were perfused with saline of the same volume, all the mice were treated for 6 continuous weeks. In the 7^th week, the learning and memory changes of the mice were observed with the Morist water maze （RB-100B round water maze） test, the training standard was that the mice found the refuge platform within 15 s for 7 times in 8 continuous training. The mice were tested for 5 times respectively at 1 hour and 1 day after training, the needed time for the mice to reach the refuge platform every time was recorded. The blood and femur of the mice were taken to detected the contents of lead in blood and femur. RESULTS： All the 50 mice were involved in the analysis of results. ① Content of lead in blood of the mice： It was significantly higher in the model control group than in the blank control group [（1.70±0.01）, （0.06±0.01） mg/kg, t=366.7, P 〈 0.01], It was significantly lower in the Lycium barbarum polysaccharides 1.8 and 3.6 g/kg groups than in the model control group [（0.30±0.23）, （0.09±0.15） mg/kg, t=19.32, 33.87, P 〈 0.05].② Content of lead in bone of the mice： h was significantly higher in the model control group than in the blank control group [（175.7±28.9）,（1.4±0.9） mg/kg, t=19.06, P 〈 0.01]; It was significantly lower in the Lycium barbarum polysaccharides 0.9, 1.8 and 3.6 g/kg groups than in the model control group [（153.5±29.3）, （132.9±28.5）, （122.8±19.6） mg/kg, t=l.71 to 3.33, P 〈 0.05]. ③ The time for the mice to reach the refuge platform： It was shortened in the Lycium barbarum polysaccharides different dosage groups as compared with that in the control group, that at after 1 hour was significantly shorter in the 3.6 g/kg group than in the model control group [（28.2±13.6）, （39.1±18.2） s, t=1.80, P 〈 0.05]. CONCLUSION： Lycium barbarum polysaccharides can effectively promote the elimination of lead in vivo in lead-exposed mice, ameliorate lead induced learning and memory damage. It can be suspected that its ameliorative effect on memory is associated with its decrease of lead in vivo.