香菇多糖对阿尔茨海默病大鼠学习记忆能力影响

Effect of lentinan on hippocampus c-fos expression and learning and memory in rats with Alzheimer's disease

目的探讨香菇多糖(LNT)对阿尔茨海默病(AD)模型大鼠学习记忆行为能力影响及机制。方法50只健康SD大鼠中随机抽取10只作为对照组(生理盐水),另40只大鼠用于制造AD模型,30只模型大鼠随机分为模型组(生理盐水)、香菇多糖高、低剂量组(50、10mg/kg);采用Morris水迷宫检测大鼠学习记忆能力,试剂盒法测定大脑皮质超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性及单胺氧化酶(MAO)含量,荧光抗体法检测大鼠海马c-fos蛋白表达水平。结果与对照组比较,模型组大鼠训练第5天逃避潜伏期[(63.67±5.19)s]明显延长、跨越平台次数[(2.09±1.22)次]明显减少(P<0.01),大脑皮质CAT、SOD活力[分别为(4.98±1.32)、(9.39±2.52)U/mgpro]明显下降(P<0.01),MAO含量[(68.62±9.67)nmol/100mgpro]明显升高(P<0.01),海马组织中c-fos表达量明显升高(P<0.01);与模型组比较,香菇多糖高剂量组大鼠训练第5天逃避潜伏期[(35.67±4.68)s]明显缩短、跨越平台次数[(4.89±1.01)次]明显增加(P<0.01),大脑皮质CAT和SOD活力[分别为(7.18±1.19)、(13.45±2.21)U/mgpro]明显升高(P<0.01),MAO含量[(38.33±6.53)nmol/100 mgpro]明显降低(P<0.01),海马组织中c-fos表达量明显减少(P<0.01)。结论香菇多糖对AD大鼠学习记忆能力具有一定改善作用,其机制可能与增强大鼠大脑抗氧化能力和降低c-fos蛋白表达有关。

Objective To investigate the effect and mechnism of lentinan （LNT） on learning and memory abilities in rats with Alzheimer＇s disease （AD）.Methods Ten rats were selected randomly as normal control group （normal saline） from 50 healthy Sprague-Dawley （SD） rats;the other 40 rats were assigned into AD model group,from which 30 model rats were randomly selected and divided into three groups：a model group （normal saline）,high dose LNT intervention group （LNT-H,50 mg/kg） and low LNT dose intervention group （LNT-L,10 mg/kg）.Then Morris water maze was used to test learning and memory abilities.Reagent-boxes were used to observe the activity of superoxide dismutase （SOD） and catalase （CAT） and content of monoamine oxidase （MAO） in cerebral cortex.c-fos expression level in hippocampus was observed by immunofluorescence assay.Results Compared with that of the control group,the escape latency （63.67±5.19 seconds） at the 5th day of the model group was significantly increased （P〈0.01）,while the times of crossing platform （2.09±1.22） were obviously decreased （P〈0.01）;in addition,for the rats of the model group,the activity of CAT （4.98±1.32） and SOD （9.39±2.52） in hippocampus were obviously decreased （P〈0.01）,the MAO content （68.62±9.67 nmol/100 mg pro）increased （P〈0.01）,and the expression of c-fos in hippocampal tissue was significantly increased （P〈0.01）.In contrast with the model group,the escape latency （35.67±4.68 s） at the 5th day was obviously shortened （P〈0.01）,while the times of crossing platform （4.89±1.01） were obviously increased in the LNT-H group （P〈0.01）;in cerebral cortex,the activity of CAT （7.18±1.19） and SOD （13.45±2.21） were obviously increased （P〈0.01） but the MAO content （38.33±6.53 nmol/100 mgpro） markedly decreased （P〈0.01）;the expression of c-fos in hippocampal tissue was significantly reduced （P〈0.01）.Conclusion Lentinan may improve learning and memory ability through enhancing antioxidant capacity of rat brain and regulating the expression of hippocampus c-fos protein in AD rats.