Effect Of Regular Exercise On Cardiac Function Of Aging Drosophila With The Heart-specific Gene Knockdown Of Ca-?1D

Objective:To study the age-related changes of Drosophila with the Heart-specific Gene Knockdown of Ca-?1D and the effects of regular exercise on the cardiac function,exercise capacity and life cycle of Drosophila with cardiac Ca-?1D gene silence at adolescence,and explore the function of Ca-?1D and training on cardiac aging.Methods:The virgin female flies with w1118;P{GD1737}v51491 genotype were crossed with W1118 flies and Hand-Gal4 flies respectively,obtained F1 generation of female flies,then the virgin female F1 progeny respectively divided into the group of two-week-old normal expression(control group),the group of six-week-old normal expression(aged group),the group of two-week-old knockdown expression(interference group),the group of six-week-old knockdown expression(aged interference Group),the group of six-week-old normal exercise group(aged exercise group),the group of six-week-old knockdown exercise group(aged exercise disturbance group).The flies in the exercise groups at 15 days old performed platform 2 hours per day for,5 days a week for 4 weeks.At the end of 6 weeks selections.The Ca-?1D mRNA expression in cardiac muscle was measure by qRT-PCR and heart function was recorded by M-mode echocardiography.The circadian rhythm changes was monitor by DAMS3 system.The exercise capacity was assessed by climbing index and lifespan was reflected by lifecycle.Results:(1)The expression of Ca-?1D in RNA interference group was approximately decreased by 50%compared to control group(P<0.01).(2)Compared with the control group,the aged group heart period(HP),systolic intervals(SI)increased(P<0.05),and diastolic intervals(DI)increased(P<0.01),bradycardia rate increased(P<0.01).diastolic diameter(DD),systolic diameter(SD),fractional shortening(FS)decreased(P<0.01).Compared with the control group,the interference group HP,SI,DI increased(P<0.01)and the bradycardia rate increased(P<0.01).DD increased(P<0.05),SD increased(P<0.01),FS decreased(P<0.01).Compared with the control group,the interference group of age HP,SI,DI increased(P<0.01),the bradycardia rate and FL increased(P<0.01).DD,SD increased(P<0.01),FS decreased(P<0.01).Compared with the interference group,the interference group of age HP increased(P<0.05),FL and bradycardia rate increased(P<0.01).Gene*age had a synergistic effect on the DI,bradycardia rate,DD,SD and FS(P<0.05).Aging is the main effect on the FL results,and the gene is the main effect of the HP and SI results.Compared with the aged group,the aged interference group SI increased(P<0.05),HP,FL,bradycardia rate increased(P<0.01),DD,SD increased(P<0.01),FS reduced(P<0.05).Compared with the aged group,the aged exercise disturbance group HP,bradycardia rate increased(P<0.01).SD,DD increased(P<0.01),FS had not significant change(P>0.05).And compared to the aged group,the aged exercise group HP,DI increased(P<0.05),bradycardia rate increased(P<0.01).Compared with the aged interference group,the interference group of aging exercise bradycardia rate reduced(P<0.01),DD rise(P<0.05).Gene silencing and endurance exercise Combined have a synergistic effect to HR(P<0.05).The primary effect of HP,DD,SD,FS,FL is gene.Exercise is the main effect of DI resulting effects.(3)Compared with the control group,the interference group of climbing ability reduce(P<0.01),the age group of climbing ability reduce(P<0.01),the interference group of age of climbing ability reduce(P<0,01).Compared with the interference group,the interference group of age of climbing ability reduce(P<0.01).Gene knock-down and aging were the factors that decreased the climbing ability of Drosophila.Compared with the aged group,the aged exercise group of climbing capacity increased(P<0.01),the aged interference group of climbing ability reduce(P<0.05);Gene silencing combined with endurance exercise have a synergistic effect to climbing ability(P<0.05).(4)The day and night activities of the control group,the intervention group,the aging group and the aged exercise group showed bimodal,and the morning peak and the evening peak appeared before and after turning on and off.Gene knockdown is the main effect of Drosophila day activity and night activity decrease.(5)The aged exercise group is higher than the average life expectancy of aged group(P<0.01),the interference group of aged exercise higher than the average life expectancy of the aged interference group(P<0.01),the aged interference group lower than the aged group(P<0.01).conclusion:(11)Aging is one of the causes of decreased systolic function,rhythm disturbance and activity level in Drosophila.(2)The normal expression of the Ca-alD gene is important for maintaining the systolic function and rhythm of the heart.The heart-specificity silence of Ca-alD gene is a primary cause to this fruit flies cardiac contraction dysfunction,the rhythm disorder as well as the loss of life.(3)Regular training can improve the exercise ability,maintain the heart normal rhythm and improve the lifespan of elderly fruit flies obviously.(4)The exercise can effectively improve the bradycardia which causes by the Ca-alD gene knockdown,has sharpened the erercise ability,but it is not remarkable improvement to the cardiac contraction function.