不同剂量补锌对大鼠学习记忆功能及海马一氧化氮合酶活性的影响

Influence of Zinc Supplementation at Different Dosage on Learning and Memory Function and NOS Activity in Hippocampus of Rats

关键词:  锌  一氧化氮合酶(NOS)  学习记忆功能  海马  大鼠

Key words:  zinc(Zn)  nitride oxide synthase(NOS)  learning and memory function  hippocampus

摘要:

[目的]探索补锌对临床亚健康干预的合理剂量,研究不同剂量补锌对脑结构和功能的影响及其相关机制。[方法]分别采用Y-型迷宫和还原性辅酶Ⅱ-黄递酶(NADPH-d)组化反应染色法,观察大鼠学习记忆功能变化及海马结构不同亚区内一氧化氮合酶(NOS)活性的变化。[结果]适量补锌(200mg/kg饲料锌水平)可使大鼠海马结构CA₁、CA₃、齿状回的一氧化氮合酶阳性神经元数增加(P<0.05),促进动物的学习记忆功能。在有限范围内超量补锌(400mg/kg饲料锌水平内),对动物的学习记忆功能无明显影响。而超过一定范围高剂量补锌(≥600mg/kg饲料锌水平)时,可损害动物的学习记忆能力,同时大鼠海马结构各区的NOS活性降低,这种变化可能是高锌干扰脑学习记忆功能的主要机制之一。[结论]适量补锌对大鼠学习记忆功能有促进作用,超量补锌对大鼠学习记忆功能有损害作用,其机制可能与海马结构各区的NOS活性变化有关。

Abstract:

[Objective] To explore the reasonable dosage of zinc supplementation for intervention with the sub-clinical patients and study the effect of zinc supplementation at different dosage on brain structure and function and their mechanism.[Methods] The change of learning and memory function and the activity of NOS(nitride oxide synthase)in different sub-unit of hippocampus in rats were observed by Y-lost-palace test and NADPH-d histochemistry.[Results] Zinc supplementation at low but adequate dosage(200 mg/kg zinc in forage)could improve the learning and memory function by increasing the activity of NOS in hippocampus construction and sub-regions of CA₁ and CA₃ and dentate gyrus of rats.Zinc supplementation with excessive dosage within a limit(400 mg/kg zinc in forage)hadn’t obvious curative effect.Excessive zinc supplementation beyond the limit(≥600 mg/kg zinc in forage)could impair the learning and memory ability and decrease the activity of NOS in hippocampus of rats.All of these might be one of the main mechanisms that excessive zinc supplementation beyond the limit could interfere with the learning and memory function.[Conclusion] Zinc supplementation at lower dosage can improve the learning and memory function of rats.Zinc supplementation at an excessive dosage can impair it.The changes of NOS activity in hippocampus may be one of the mechanisms of zinc affecting the learning and memory.