维生素B_(12)影响同型半胱氨酸对大鼠认知能力的作用

目的:观察同型半胱氨酸(homocysteine,Hcy)对大鼠空间认知能力的影响及维生素B12(VB12)的干预作用。方法:大鼠随机分为对照组,实验组及VB12干预组。测定各组血浆Hcy,血清VB12水平和Y迷宫学习记忆情况,并对大鼠海马区进行乙酰胆碱酯酶(acetylcholinesterase,AChE)免疫组化分析。结果:实验组血浆Hcy水平比对照组升高,并出现空间认知障碍,且两组差异有显著性;实验组海马区AChE阳性纤维减少,呈弱阳性(+)。VB12干预组血浆Hcy水平与对照组比无明显变化,但VB12升高,无空间认知障碍发生;VB12干预组海马区有大量的AChE纤维,呈强阳性(+++)。结论:高同型半胱氨酸可引起大鼠空间认知障碍,而VB12可降低Hcy水平并干预空间认知障碍的发生。

THE PROTECTIVE EFFECTS OF VITAMIN B12ON SPATIAL COGNITIVE ABILITY IMPAIRED BY HOMOCYSTEINE IN RATS

Objective: To observe the relationship between homocysteine(Hcy)and spatial cognitive ability and to evaluate whether vitamin B12 supplementation could protect spatial cognitive ability in rats. Methods: The rats were randomized into three groups. The experimental group was given methionine subcutaneously. The intervention group was given methionine and vitamin B12 subcutaneously. The control group received isometric normal saline. After being raised for 8 weeks, all rats were examined for plasma Hcy and serum vitamin B12 and scores of Y-maze test. The brain tissues of hippocampus were checked immunohistochemically for acetylcholinesterase (AChE). Results: The experimental group developed hyperhomocysteinemia and descreased spatial cognitive ability significantly (P<0.001). The AChE activity in hippocampus was also descreased. The intervention group displayed normal Hcy level and increased vitamin B12 level and spatial cognitive ability was not significantly different compared with control rats (P >0.05). Conclusion: Homocysteine can impair the spatial cognitive ability in rats and vitamin B12 is effective in lowering Hcy level and protect the spatial cognitive ability of rats.