霍山石斛通过上调突触蛋白Arc表达增强衰老小鼠学习记忆的研究

目的 探讨霍山石斛对小鼠学习记忆能力减退的影响及其可能机制.方法 将33只SPF级C57BL/6小鼠随机分为模型组、早期给药组和晚期给药组,另取11只12周龄C57BL/6青年小鼠作为对照组.采用Morris水迷宫检测小鼠学习记忆能力;应用透射电子显微镜观察海马CA3区超微结构,采用免疫印迹检测海马CA3区Arc蛋白的表达水平.结果 与对照组比较,模型组小鼠游泳距离显著延长(P<0.05),靶象限游泳时间明显减少(P<0.05);与模型组比较,早期给药组小鼠游泳路程显著缩短(P<0.05),靶象限游泳时间显著延长(P<0.05).透射电子显微镜显示,早期给药组和对照组小鼠海马CA3区可见较多结构清晰的线粒体,线粒体嵴排列较整齐,突触结构较清晰且较多;模型组和晚期给药组小鼠较多出现线粒体空泡化和嵴断裂或扭曲,线粒体数量和突触数量减少,突触后膜较致密.与对照组比较,模型组小鼠海马CA3区Arc表达水平显著降低(P<0.05);与模型组比较,早期给药组小鼠CA3区Arc表达水平显著升高(P<0.05).结论 早期给予霍山石斛可以延缓或预防小鼠学习记忆能力减退,其机制可能与其上调突触蛋白Arc的表达水平进而影响海马突触结构有关.

Dendrobium huoshanense Enhances Learning and Memory in Senescent Mice by Upregulating the Expression of Synaptic Protein Arc

Objective To investigate the effect of Dendrobium huoshanense on the decline of learning and memory in mice and its possible mechanism. Methods A total of 33 specific pathogen-free C57BL/6 mice were randomly divided into model group, early administration group, and late administration group, and another 11 C57BL/6 mice, aged 12 weeks, were selected as control group. Morris water maze was used to evaluate learning and memory ability; transmission electron microscopy was used to observe the ultrastructure of the hippocampal CA3 region; Western blot was used to measure the protein expression level of Arc in the hippocampus CA3 region. Results Compared with the control group, the model group had a significant increase in the swimming distance (P<0.05) and a significant reduction in the swimming time in target quadrant(P<0.05); compared with the model group, the early administration group had a significant reduction in swimming distance(P<0.05) and a significant increase in swimming time in target quadrant(P<0.05). Transmission electron microscopy showed that there were many mitochondria with clear structure in hippocampal CA3 region of mice in early administration group and control group, the mitochondrial cristae arranged orderly, and the synaptic structure was clear and more. In aging model group and late administration group, mitochondria vacuolization and cristae fracture or distortion occurred frequently, the number of mitochondria and synapses decreased, and the postsynaptic membrane was dense. Compared with the control group,the model group had a significant reduction in the protein expression level of Arc in the hippocampal CA3 region (P<0.05), and compared with the model group, the early administration group had a significant increase in the protein expression level of Arc in the hippocampal CA3 region (P<0.05). Conclusion Early administration of Dendrobium huoshanense can delay or prevent the decline of learning and memory in mice, possibly by upregulating the expression of synaptic protein Arc and thus affecting hippocampal synaptic structure.