耐力运动联合NAD合成酶基因CG9940过表达对中老龄果蝇心脏功能、运动能力和寿命的影响

Endurance Training Improves Exercise Capacity,Delays Recession of Cardiac Function,Extends Lifespan,Reduces Arrhythmia and Diastolic Dysfunction in Elderly Drosophila Carrying Overexpression of NAD CG9940 Synthetase Gene

目的:探讨耐力运动、NAD合成酶相关基因CG9940以及耐力运动联合CG9940基因过表达对中老龄果蝇心脏功能、运动能力和寿命的影响。方法:y[1]w[67c23]P{y[+m8]=Mae-UAS.6.11}CG9940[GG01267]雌性果蝇分别与W1118雄性果蝇、arm-Gal4雄性果蝇杂交取F1代分为对照组、运动组、过表达对照组和过表达运动组,4组均收集400只处女蝇,饲养至30天龄开始训练,连续训练5天,次日取材。实时荧光定量PCR测定CG9940基因m RNA表达量,M-mode心动图检测心管收缩时间、收缩直径、舒张直径、舒张功能不全指数、射血分数和心律失常指数,测量攀爬指数,统计生命周期。结果:(1)过表达对照组CG9940 m RNA过表达率为155.2%,过表达运动组的过表达率为152.0%。(2)与对照组相比,运动组心率降低(P<0.01),射血分数增大(P<0.01),舒张功能不全指数降低(P<0.05);过表达对照组心率降低(P<0.05),射血分数增大(P<0.01);过表达运动组心率降低(P<0.01),心脏平均收缩速度增大(P<0.05),射血分数增大(P<0.01),舒张功能不全指数减小(P<0.01),心律失常指数降低(P<0.05)。与运动组相比,过表达运动组心率降低(P<0.05),射血分数增大(P<0.01),舒张功能不全指数减小(P<0.05)。与过表达对照组相比,过表达运动组心率降低(P<0.05),射血分数增大(P<0.05),舒张功能不全指数减小(P<0.01)。(3)运动组攀爬指数高于对照组(P<0.05);过表达运动组攀爬指数高于对照组(P<0.01)和过表达对照组(P<0.05)。(4)运动组寿命高于对照组(P<0.05);过表达对照组寿命高于对照组(P<0.01);过表达运动组寿命高于对照组(P<0.01)、运动组(P<0.01)和过表达对照组(P<0.05)。结论:耐力运动能够提高中老年果蝇运动能力并且能延缓心脏功能性衰退和延长生命周期;NAD合成酶基因CG9940过表达能够延缓果蝇心脏衰老,显著延长果蝇寿命;耐力运动联合CG9940基因过表达能降低中老龄果蝇心律失常和舒张功能不全,同时能增强中老龄果蝇逆重力攀爬特征,提高活动能力,并且延寿效果更好,表明二者对中老龄果蝇抗衰老产生叠了加效应。

Objective To study the effects of overexpression of nicotinamide adenine dinucleotide （NAD） synthase genes CG9940 and endurance training on cardiac function, exercise capacity and lifespan in elderly drosophila melanogaster. Methods Virgin drosophila females carrying y[1]W[67c23]＋P{Y[＋8]=Mae-UAS.6.11}CG9940[GG01267] were cross-fertilized respectively with drosophila males carrying Wms and carrying arm- Gal4. And their F-1 progeny virgin females were respectively divided into control group （C）, exercise group（E）, overexpression control group （OC）,and overexpression exercise group （OE）. Groups E and OE group began training 30 days after birth and lasted for 5 days. Expression of CG9940 gene mRNA was detected by real-time PCR. The heart tube diastolic diameter, systolic diameter, fractionalshortening, systolic interval, diastolic dysfunction index and arrhythmia index of the flies were detected by M-mode echocardiography, and their climbing index was measured at 35-day-old, and lifespan was calculated at 40-days-old. Results （1）The expressions rates of CG9940 gene mRNA in group OC and OE are 155.2% and 152%. （2）Compared with group C ,heart rate decreases （P 〈 0.01 ）,fractional shortening increases（P 〈 0.01 ）, diastolic dysfunction index decreases （P 〈 0.05）in group E. Heart rate in group OC is lower than that in group OE （P 〈 0.05） ,fraction shortening in group OC is larger than group C（P 〈 0.01 ） ,heart rate in group OE is lower than in group C（P 〈 0.01） ,group E （P 〈 0.05）,and group OC （P 〈 0.05）,average systolic speed in group OE is faster than in group C （P 〈 0.05）,fraction shortening in group OE is larger than in group C （P 〈 0.01 ）,group E（P 〈 0.01 ）, and group OC （P 〈 0.05） ,diastolic dysfunction index in group OE is lower than that in group C （P 〈 0.01 ）, group OC（P 〈 0.01 ）,and group E（P 〈 0.05）,and arrhythmia index in group OE is lower than in group C（P 〈 0.05）. （3）Climbing Index of group E is greater than group C （P 〈 0.05）and group OC （P 〈 0.05）. （4） Comparing to group C,lifespan of groups E and OC prolongs （P 〈 0.05 and P 〈 0.01）,and the average prolonged rate of lifespan in group OC and OE is 6.8% and 11.5%. The highest life expectancy of groups C, E, OC ,and OE is 67,67,77 ,and 78 days,respectively. Conclusion Endurance training improves the exercise ability, delays the cardiac functional decline and improves the hfespan of elderly fruit flies obviously, and the combination of endurance training and overexpression of NAD CG9940 synthetase gene not only can delay the cardiac functional decline and improve lifespan,but also reduce arrhythmia and diastolic dysfunction, prevent heart failure of elderly fruit flies.