MiR-199a-targeted MTOR Regulates Exercise-induced Cardiac Hypertrophy In Zebrafish

Objective:The aim of the study was to observe the mRNA expression of mRNA,mTOR phosphorylation and protein expression,p70s6k protein expression under different exercise time and different exercise load,to study the changes of p70s6k protein expression in cardiac myocytes under different load and time.And the influence of exercise on the regulation of myocardial protein metabolism was discussed from molecular biology point of view.Methods:150 healthy adult male zebrafish were randomly divided into 4 weeks and 8 weeks of static control group(C),4 weeks of constant load(E1),4 weeks incremental load group E2),8 weeks constant load group(H1),8 weeks incremental load group(H2).The quiet control group was kept for 4 or 8 weeks under the above-mentioned feeding method.The training group referred to Wood,Pelster[1,2]method training 4,8 weeks,the first week of training every morning drive 5 min/time,after seven weeks of training volume unchanged.Every afternoon to drive training 5 min,from the second week,the daily training volume unchanged in the afternoon plus 1 min per week.That is,the second week of the afternoon training time of 6 min,the remaining weeks were accumulated.4 weeks after feeding or training,were drawn;8 weeks after feeding or training,were drawn.The animals were sacrificed 24 hours after the last exercise.The hearts were dissected and anesthetized.The mRNA expression of miR-199a and mTOR in the zebrafish were detected by real-time fluorescent quantitative PCR.The expression of miR-199a and mTOR mRNA were detected by Western blot.The zebrafish tissues of each group were measured by HE staining.The expression of mTOR protein and phosphorylated protein,p70S6K protein expression in fish heart.Results:(1)Heart coefficient:Compared with group C,the heart rate coefficient of zebrafish in E1 group,E2 group,H1 group and H2 group increased significantly(P<0.01);the cardiac coefficient of zebra fish in E2 group and H2 group was significantly higher than that in E1 group(P<0.01).The cardiac coefficient of zebrafish in group H2 was also significantly higher than that in group H1(P<0.01).(2)miR-199a mRNA:Compared with group C,the expression of miR-199a mRNA in zebrafish group E1 and group H2 increased significantly(P<0.05).Compared with group E1,miR-199a mRNA expression in zebrafish E2 group and H2 group was significantly different(P<0.01).Compared with H1 group,the expression of miR-199a mRNA in zebrafish group also increased significantly(P<0.01).(3)mTOR mRNA:Compared with group C,the expression of miR-199a mRNA in zebrafish group El and group H2 increased significantly(P<0.05).Compared with group E1,miR-199a mRNA expression in zebrafish E2 group and H2 group was significantly different(P<0.01).Compared with H1 group,the expression of miR-199a mRNA in zebrafish group also increased significantly(P<0.01).(4)mTOR protein expression and phosphorylation:Compared with group C,the expression of mTOR protein in E1 group,E2 group,H1 group and H2 group was significantly different(P<0.01).Compared with E1 group,There was no significant difference in the expression of mTOR protein between zebrafish group and H2 group(P>0.05).Compared with H1 group,the expression of mTOR protein in zebrafish group had no significant difference(P>0.05).Compared with group C,the mTOR phosphorylation of zebrafish in group E1,group E2,group H1 and group H2 were significantly different(P<0.01).Compared with group E1,(P<0.01).Compared with H1 group,the expression of mTOR phosphorylation in zebrafish group was significantly different(P<0.05).(5)The expression of P70S6K protein:Compared with group C,the expression of P70S6K protein was significantly increased in E1 group,E2 group,H1 group and H2 group(P<0.01),and the expression of P70S6K protein in zebrafish group(P<0.01).Compared with H1 group,the expression of P70S6K protein in the H2 group increased slightly(P<0.05).Conclusions:(1)Long-term exercise induced myocardial hypertrophy of zebrafish,and the extent of myocardial hypertrophy was associated with motor strength.(2)The volume of myocardial cells in zebrafish was sig nificantly enlarged,the length lengthened,the diameter in creased,and the physiological changes were made.(3)In the process of exercise-induced myocardial hyper trophy miR-199a express,and target of muscle cell differen tiation plays a very important mTOR signaling pathways,miR-199a direct ratio relation between the expression of mTOR.(4)The motor stimulated mTOR,and the four-week load intensity movement mTOR expression was less varied than the 8 week load intensity exercise.