Keloglan S, Sahin L, Cevik O S
Department of Nursing, Faculty of Health Sciences, Amasya University, Amasya, Turkey.
Department of Physiology, Faculty of Medicine, Mersin University, Mersin, Turkey.
Folia Morphol (Warsz). 2019;78(4):668-675. doi: 10.5603/FM.a2019.0018. Epub 2019 Feb 28.
Some environment enrichments such as exercise has been reported to improve the diminished cognitive functions and related gene expression. Therefore, we aimed to investigate the effects of prolonged treadmill exercise on long-term learning and hippocampal gene expression, which involves learning and plasticity.
Male Wistar rats (n = 32) randomly assigned into four groups: control (C), social isolation (SI), exercised (E), social isolation + exercise (SE) during postnatal days (PNDs) 21-34. Social isolation protocol was applied during 14 days by placing the rat alone in a cage. Rats were exercised daily, 5 days per week, for overall 4 weeks. Finally, learning performance was evaluated by the novel object recognition test. At the end of learning test, the rats were decapitated to isolate hippocampus tissues for learning related gene expression such as N-methyl-d-aspartate receptor (NMDAR) subunit genes (Grin1, Grin2a, Grin2b) and cyclin dependent kinase 5 (Cdk5), Cdk5 regulatory subunit p35 (Cdk5r), activity-regulated, cytoskeletal-associated protein (Arc), the immediate early gene (c-Fos, a marker of neuronal activation), doublecortin (DCX), achaetescute homolog 1 (ASCL1), brain-derived neurotrophic factor (BDNF) by real-time polymerase chain reaction (RT-PCR).
Grin1, NMDAR subunit gene expression was increased significantly in E group compared to other groups. Grin2b, NMDAR subunit gene expression was increased in E group compared to the SI group. Cdk5 level increased in E group compared to the SE group. The ASCL1 gene expression increased in E group compare to the SE group. The DCX gene expression increasing in C group compared to SI and SE groups.
Taken together these findings may point out that long-term social isolation down-regulated learning-related genes. However, treadmill exercise together with social isolation did not restore this down-regulation although treadmill exercise increased learning-related genes without improving cognitive behaviour.
据报道，一些环境富集措施，如运动，可改善认知功能减退及相关基因表达。因此，我们旨在研究长期跑步机运动对长期学习及海马体基因表达的影响，这涉及学习和可塑性。
将32只雄性Wistar大鼠随机分为四组：对照组（C）、社会隔离组（SI）、运动组（E）、社会隔离+运动组（SE），在出生后第21至34天进行实验。通过将大鼠单独置于笼中，实施为期14天的社会隔离方案。大鼠每周运动5天，每天运动，共持续4周。最后，通过新物体识别测试评估学习表现。在学习测试结束时，将大鼠断头以分离海马体组织，通过实时聚合酶链反应（RT-PCR）检测与学习相关的基因表达，如N-甲基-D-天冬氨酸受体（NMDAR）亚基基因（Grin1、Grin2a、Grin2b）、细胞周期蛋白依赖性激酶5（Cdk5）、Cdk5调节亚基p35（Cdk5r）、活性调节细胞骨架相关蛋白（Arc）、即刻早期基因（c-Fos，神经元激活标志物）、双皮质素（DCX）、achaetescute同源物1（ASCL1）、脑源性神经营养因子（BDNF）。
与其他组相比，E组中Grin1（NMDAR亚基基因）表达显著增加。与SI组相比，E组中Grin2b（NMDAR亚基基因）表达增加。与SE组相比，E组中Cdk5水平升高。与SE组相比，E组中ASCL1基因表达增加。与SI组和SE组相比，C组中DCX基因表达增加。
综合这些发现可能表明，长期社会隔离会下调与学习相关的基因。然而，尽管跑步机运动增加了与学习相关的基因，但并未改善认知行为，且与社会隔离一起并未恢复这种下调。
