有氧运动对APP/PS1小鼠大脑皮质和海马组织Keap1/Nrf2信号通路的影响

The Effect of Aerobic Exercise on Keap1/Nrf2 Pathway in the Cerebral Cortex and Hippocampus of APP/PS1 Mice

目的:探讨有氧运动对APP/PS1小鼠大脑皮质和海马组织Keap1/Nrf2信号通路的影响,为揭示有氧运动防治阿尔兹海默症提供理论基础。方法:雄性APP/PS1小鼠随机分为安静对照组(CG)和运动组(EG)。EG组小鼠进行为期8周的跑台训练,速度从12 m/min增至15 m/min,训练时间从30 min增至60 min。最后一次训练结束后48小时,分离所有小鼠大脑皮质和海马组织。通过荧光定量PCR和West-ern blot检测各组小鼠大脑皮质和海马组织中结构蛋白Keap1、Nrf2和Maf及下游抗氧化蛋白HO-1、NQO1和GCLC的mRNA及蛋白含量;通过Western blot检测APP、Aβ42和BACE1的蛋白含量;通过试剂盒检测MDA和GSH含量及GSH-Px和T-SOD活力。结果:8周跑台训练后,EG组小鼠大脑皮质和海马组织Keap1 mRNA和蛋白含量与CG组相比无显著性差异,而Nrf2和Maf mRNA和蛋白含量均显著高于CG组;EG组HO-1、NQO1和GCLC mRNA和蛋白含量均显著高于CG组;EG组MDA含量显著低于CG组,而GSH含量、GSH-Px和T-SOD活力显著高于CG组;APP蛋白含量与CG组相比未发生显著改变,但Aβ42和BACE1的蛋白含量显著低于CG组。结论:有氧运动增强APP/PS1小鼠大脑皮质和海马组织中Keap1/Nrf2信号通路活性;提高该通路下游抗氧化蛋白HO-1、NQO1和GCLC的含量;降低大脑皮质和海马组织氧化应激水平;从而有效抑制Aβ蛋白的形成。

Objective To explore the effect of aerobic exercise on Kelch-like ECH-associated protein 1（Keap1）/nuclear factor erythroid 2 p45-related factor 2（Nrf2） pathway in the cerebral cortex and hippocampus of amyloid β-protein precursor（APP）/PS1 mice,so as to provide a theoretical basis for conforming that aerobic exercise can prevent Alzheimer＇s disease. Methods APP/PS1 male mice were randomly assigned to a sedentary control group（CG） and an aerobic exercise group（EG）. The mice in the EG group underwent an 8-week treadmill training,running progressively from 12 min/day at 30 m/min,up to 15 min/day at 60 m/min. Their cerebral cortex and hippocampus were isolated at 48 h after the last exercise. The mRNA and protein levels of structural proteins Keap1,Nrf2,muscloaponeurotic fibrosarcoma protein（Maf） and downstream antioxidant proteins including the heme oxygenase 1（HO-1）,NADPH dehydrogenase quinone 1（NQO1） and glutamate-cysteine ligase catalytic subunit（GCLC） were analyzed using the quantitative polymerase chain reaction（PCR） and Western blotting. The protein levels of amyloid β-protein precursor（APP）,amyloid β-protein（Aβ42） and Beta-secretase 1（BACE1）were analyzed using the Western blotting. The malondialdehyde（MDA） and glutathione（GSH） content,glutathione peroxidase（GSH-Px） and total superoxide dismutase（T-SOD） activity were determined using the assay kit. Results After 8 weeks of treadmill exercise,there were no significant differences in Keap1 mRNA and protein levels between the EG and CG groups,but the mRNA and protein levels of Nrf2 and Maf in the EG group were significantly higher than those in the CG group. The mRNA and protein levels of HO-1,NQO1 and GCLC were significantly higher than those in the CG group. Meanwhile,the MDA content in the EG group were significantly lower than those in the CG group,while the GSH content,GSH-Px and T-SOD activity were significantly higher than those in the CG group.Although there were no significant differences in APP protein levels between group EG and CG,the protein levels of Aβ42 and BACE1 of group EG were significantly lower than those of group CG. Conclusion Aerobic exercises can enhance the activity of Keap1/Nrf2 pathway,increase the content of HO-1,NQO1 and GCLC,as well as reduce the oxidative stress in the cerebral cortex and hippocampus,which works together to inhibit the formation of Aβ.