目的：探讨低氧和运动训练对大鼠学习记忆的作用和交互作用及其与突触可塑性之间的关系。方法：采用交互设计的研究方案对SD大鼠进行8周的14．2％的低氧暴露或／和60 min的无负重游泳训练后，通过 Morris水迷宫检测大鼠的学习和记忆能力，观察大鼠海马的超微结构，并检测海马神经生长相关蛋白‐43（GAP‐43）、突触素（SYP ）和神经细胞粘附因子（NCAM ）mRNA的表达量。结果：1）长期的低氧暴露可使大鼠的潜伏期显著增加（ P＜0．05），穿越平台的次数显著减少（P＜0．05），运动训练能使大鼠的潜伏期显著缩短（P＜0．05），穿越平台的次数显著增加（ P＜0．05），低氧联合运动训练对缩短大鼠潜伏期、提高大鼠穿越平台次数没有显著的交互作用（ P＞0．05）。2）与 NC组比较，HC组海马突触数量和突触小泡少，突触间隙模糊不清。与NE组相比，HE组海马内突触数量以及突触小泡数量有所减少，突触后膜致密物质（PSD ）厚度减小。3）长期低氧暴露可使大鼠海马区 GAP‐43、NCAM mRNA表达显著降低（P＜0．05），SYP mRNA表达下降，但无显著性差异（P＞0．05），运动训练可使大鼠海马GAP‐43、SYP、NCAM mRNA表达显著增加（ P＜0．05，P＜0．01），在低氧条件下进行运动训练对提高GAP‐43、SYP、NCAM mRNA表达没有显著的交互作用（ P＞0．05）。结论：1）长期的低氧暴露可抑制学习记忆能力，而运动训练能够增强学习记忆能力，虽然运动训练在一定程度上可以改善低氧暴露大鼠的学习记忆能力，但是并不能完全逆转低氧暴露所造成的学习能力下降。2）长期的低氧暴露或运动训练通过下调或上调海马GAP‐43、SYP和NCAM mRNA的表达，抑制或增强海马突触结构的可塑性，可能是影响学习记忆能力的重要机制。%Objective :To investigate the action and interaction of hypoxia and exercise training on learning and memory and its relation with synaptic plasticity in rats .Methods :Used the experi‐mental scheme of interaction design ,SD rats were submitted 14 .2% hypoxia exposure or /and 60 min no‐load swimming training for 8 weeks ,the learning and memory ability of rats was measured by Morris water maze test ,the ultrastructure of hippocampus was observed ,and the expression of GAP‐43 ,NCAM ,SYP mRNA in hippocampus were detected .Results :1 )long‐term hypoxic exposure could significantly increase latency ( P< 0 .05 ) and decrease times of cross platform ( P< 0 .05 ) ,exercise training could significantly decrease latency ( P< 0 .05 ) and increase times of cross platform (P<0 .05) ,hypoxia and exercise training had no signifi‐cant interaction on decreasing the latency and improving the times of across platform ( P>0 .05) .2)Compared with group NC ,in group HC ,hippocampal synaptic number and synaptic vesicles were less ,the synaptic gap was ambiguous .Compared with group NE ,in group HE , hippocampal synaptic number and synaptic vesicles were decreased ,postsynaptic densities (PSD) was thickness .3)Chronic hypoxia exposure could cause the decrease of GAP‐43 and NCAM mRNA expression in the hippocampus significantly ( P< 0 .05 ) ,SYP mRNA expres‐sion decreased ,but it was no significant difference (P> 0 .05) ,exercise training could signifi‐cantly increase the GAP‐43 ,SYP and NCAM mRNA expression in hippocampus ( P< 0 .05 ,P<0 .01) ,hypoxia and exercise training had no significant interaction for improving the GAP‐43 ,SYP and NCAM mRNA expression ( P> 0 .05 ) .Conclusion :1 )Long‐term hypoxic expo‐sure could inhibit the ability of learning and memory ,and exercise training could increase the a‐ bility of learning and memory ,while exercise training can improve the ability of learning and memory of rats exposed to hypoxia in a certain extent ,but not completely reversed the decrease of learning and memory ability induced by hypoxia exposure .2)The long‐term hypoxia or exer‐cise training could inhibit or enhance the synaptic plasticity of hippocampal structure by down regulation or up regulation of GAP‐43 ,SYP and NCAM mRNA expression in the hippocam‐pus ,it might be an important mechanism of learning and memory ability .
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