大豆异黄酮对去卵巢大鼠学习记忆和脑内神经递质的影响

Influence of Isoflovone on Learning and Memory and Monoamine Neuro-transmitter in Ovariectomized Rats

目的:探讨大豆异黄酮(isoflovone,IS)对去卵巢大鼠空间学习记忆和脑内单胺类递质的影响。方法:选用青年SD雌性大鼠,去除双侧卵巢造模。随机分为6组,对照组、模型组、苯甲酸雌二醇组、大豆异黄酮低、中、高剂量组。苯甲酸雌二醇组给大鼠苯甲酸雌二醇ip 0.2 mg·kg-1每周1次,IS低、中、高剂量组剂量分别ig给以大豆异黄酮30,60,120 mg·kg-1·d-1,共3个月。观察各组大鼠Morris水迷宫学习能力,高效液相检测海马内单胺类神经递质,放射免疫法测定下丘脑内促性腺激素释放激素(gonadotropin-releasing hormone,GnRH)的含量。结果:①与对照组比较,模型组前3 d定位航行学习能力和空间探索能力明显降低(P<0.05);与模型组比较苯甲酸雌二醇组、IS中剂量组前3 d定位航行学习能力和空间探索能力明显提高(P<0.05)。②与对照组比较模型组海马去甲肾上腺素(norepinephrine,NE),多巴胺(dopamine,DA),5-羟色胺(5-hydroxytryptamine,5-HT)含量明显降低(P<0.05);与模型组比较IS高剂量组海马NE含量增高(P<0.05);与模型组比较中剂量组和苯甲酸雌二醇组海马DA和5-HT含量明显增高(P<0.05)③与对照组比较模型组GnRH含量明显增高(P<0.05);与模型组比较苯甲酸雌二醇组、IS中、高剂量组GnRH含量明显降低(P<0.05)。结论:中剂量大豆异黄酮通过提高海马内NE,DA,5-HT含量,降低海马GnRH含量,提高去卵巢大鼠空间学习记忆能力。

Objective： To explore the effects and mechanisms of isoflovone （IS） on spatial learning, memory and monoamine neuro-transmitte, gonadotropin-releasing hormone （GnRH） inovariectomized rats. Method： The fifty Sprague-Dawley rats were ovariectomized. Ovariectomized rats were randomly divided into five groups, model group, estradiol benzoate （EB） group, IS low dose group, IS middle dose group, IS high dose group. EB group were treated with estradiol benzoate （0.2 mg ·kg^-1 ） by intraperitoneal injection once a week. IS groups were treated with IS （30, 60, 120 mg ·kg^-1·d^-1 ） by gavage one time daily. The spatial learning and memory performance were evaluated with Morris watermaze task. The contents of monoamine neuro-transmittcr in hippocampus were measured, and GnRH in hypothalamus was measured. Result： （1） As compared with control group, the latency period of model group increased significantly （P 〈 0.05） Compared with model group, the latency period of EB group and IS middle dose group decreased significantly （P 〈 0.05）. （2）As compared with control group contents of norepinephrine （NE） , dopamine （DA） and 5-hydroxytryptamine （5-HT） in hippocampus of model group decreased significantly （P 〈 0.05 ）. As compared with model group, contents of NE in hippocampus of IS high dose group increased significantly （P 〈 0.05）. As compared with model group, contents of DA and 5-HT in hippocampus of IS middle dose group, EB group increased significantly （P 〈 0.05 ）. （3）As compared with control group, contents of GnRH in hypothalamus of model group increased significantly （P 〈 0.05）. As compared with model group, contents of GnRH in hypothalamus of IS middle and high dose group, EB group decreased significantly （P 〈 0.05 ）. Conclusion： Isoflovone can improve the ovariectomized rats＇ impairment of spatial learning and memory by increasing contents of NE, DA, 5-HT in hippocampus. Otherwise, isoflovone can decrease contents of GnRH in hypothalamus.