有氧运动改善AD模型中枢神经元线粒体通透性转换孔功能

Aerobic Exercise Modulates Mitochondrial Permeability Transition Pore Function in APP/PS1 Transgenic Mice

目的:观察12周规律有氧运动对APP/PS1双转基因小鼠中枢神经元线粒体通透性转换孔(mitochondrial permeability transition pore,m PTP)功能的影响。方法:6月龄雄性APP/PS1小鼠(AD模型)及C57BL/6J小鼠随机分为AD安静组(AS)、AD运动组(AE)、正常安静组(CS)、正常运动组(CE)。CE、AE组进行12周规律跑台运动,5 d/周,60 min/d。前10 min运动速度12 m/min,后50 min运动速度15 m/min,跑台坡度为0°。免疫组织化学、免疫荧光染色及Dot blot检测Aβ低聚物及多聚体含量;荧光染色检测m PTP开放程度; Western blot检测Cyp D、ANT1、ANT2、VDAC-1、COXIV、ABAD蛋白的相对含量;比色法检测COXIV、ABAD蛋白酶活性。结果:1) 9月龄AD组额叶皮层、海马出现明显病理性Aβ沉积,低聚物Aβ显著增加(P<0. 05);运动显著降低额叶皮层、海马多聚体Aβ斑块直径和分布区域(P<0. 05)以及低聚物Aβ含量(P<0. 05)。2)运动显著降低AD组额叶皮层、海马m PTP开放程度(P<0. 05);降低正常对照组额叶、海马m PTP的开放程度(P<0. 05)。3)运动显著降低AD组额叶皮层、海马m PTP相关组成蛋白Cyp D、ANT1及海马的VDAC-1表达(P<0. 05),提高ANT2蛋白表达(P<0. 05);同时显著降低正常对照组额叶皮层、海马Cyp D蛋白表达(P<0. 01),提高额叶皮层ANT2蛋白表达(P<0. 05)。4)运动显著提高AD组海马与线粒体功能相关的COXIV蛋白表达及活性(P<0. 05),提高额叶COXIV活性;降低海马ABAD蛋白表达,提高其活性(P<0. 01);同时提高正常对照组额叶、海马COXIV蛋白表达及活性(P<0. 05)。结论:12周规律有氧运动训练可有效地抑制9月龄APP/PS1双转基因小鼠Aβos含量及多聚体Aβ沉积,减少Aβ与m PTP相关组成蛋白Cyp D、ANT1、ANT2、VDAC-1相互作用,上调线粒体氧化磷酸化相关蛋白酶ABAD、COXIV的活性,进而调控m PTP的开放程度,增强线粒体能量代谢功能,是有氧运动促进神经可塑性的分子机制之一。

Objective: This study observed the effects of 12 weeks of aerobic exercise on mitochondrial permeability transition pore( m PTP) function in 9-month-old APP/PS1 transgenic mice. Methods: APP/PS1 transgenic mice( 6-month-old) and C57 BL/6 J mice( 6-month-old) were randomly divided into two groups respectively: exercise( CE,AE) and sedentary( AS,CS) groups. The CE and AE mice ran on the treadmill at 12 m/min( the first10 min) or 15 m/min( the following 50 min) for 60 min,0° slope,5 d/week,for 12 weeks. The levels of Aβ and soluble amyloid-β peptide oligomers( Aβos) were tested by immunofluorescence,immunohistochemistry and Dot blot;m PTP open level was detected by immunofluorescence;the protein levels of cyclophilin( Cyp D),adenine nucleotide translocase ANT1,ANT2 and voltage dependent anion channel-1( VDAC-1),COXIV,ABAD,were measured by Western blot;and the activity of cytochrome coxidase( COXIV) and alcohol dehydrogenase( ABAD) were detected by Colorimetry. Results: 1) Aβ was aggregated at the cortex and hippocampus in 9-month-old APP/PS1 transgenic mice( AS) and accompanied with a marked increase of o Aβ( P<0.05). There was a decline was detected in Aβ plaque burden and o Aβ content in AE than those of AS( P<0.05). 2) Compared with AS and CS respectively,the m PTP in frontal cortex and hippocampus in AE and CE decreased after 12 weeks intervention( P<0.05). 3) Compared with AS,the expressions of Cyp D,ANT1 and VDAC-1 in the prefrontal cortex and hippocampus in AE decreased after 12 weeks intervention( P<0.05),and the ANT2 increased( P<0.05). Compared with CS,the expression of Cyp D in CE decreased after 12 weeks intervention( P<0.05),and the ANT2 in CE increased( P<0.05). 4) Compared with AS,the expression and activity of COXIV protein related to mitochondrial function in hippocampus in AE increased after 12-week exercise( P<0.05),the activity of COXIV increased,the expression of ABAD decreased but its activity increased( P<0.01);compared with CS,the expressions of COXIV protein related to mitochondrial function in hippocampus in CE increased after 12-week exercise( P< 0.05). Conclusions: The 12-week regular aerobic exercise training can effectively inhibit the content of Aβos and Aβ in 9-month-old APP/PS1 transgenic mice,reduce the interaction between Aβ and m PTP-related proteins Cyp D,ANT1,ANT2,VDAC-1,and increase the activity of mitochondrial oxidative phosphorylation-related proteases ABAD and COXIV,thereby regulating the openness of m PTP and enhancing the energy metabolism function of mitochondria,which is one of the molecular mechanisms that aerobic exercise promotes neuroplasticity.