Effect Of Exogenous Nitrate On Myocardial Oxidative Stress In One-time Exhausted Rats

Objective:In this experiment,rats were fed with nitrate.We want to know,if the metabolism of dietary nitrate in the body can improve performance.Oxidative stress was evaluated by change of total antioxidant capacity,malondialdehyde and superoxide dismutase,for analysis the effects of different concentrations of nitrate on oxidative stress level,peroxisome proliferator-activated receptor gamma coactivator1-alpha,Lonp1 and nuclear factor of activating T cells 5 in cardiomyocytes.Method:Eight-week-old rats were randomly divided into a quiet control group?CP group?,a exercise control group?EP group?,a low-dose NaNO₃ group?ELN group?,a mid-dose NaNO₃ group?EMN group?,and a high-dose NaNO₃ group?EHN group?,8 in each group.Gavage was given for 6 days and once a day.The concentration of NaNO₃ in the ELN group was 0.3mmol/kgBW/d,0.7mmol/kgBW/d in the EMN group,1.0mmol/kgBW/d in the EHN group,and the same dose of normal saline in the CP group and the EP group.Three days adaptive low-intensity treadmill training was conducted,and one-time exhaustion treadmill experiment was started 3 hours after the last gavage.Result:1.Compared with CP group,in the EP group MDA increased?P<0.05?,SOD and T-AOC decreased?P<0.05?.Lonp1,NFAT5 protein expression decreased?P<0.01?,the difference was statistically significant.There was no significant change in the expression of PGC-1?and NO levels.2.Compared with the EP group.The levels of NO in ELN,EMN and EHN groups were increased?P<0.05 in ELN group and P<0.01 in other groups?,and the results were statistically significant.There was no significant change in T-AOC.3.The levels of SOD in ELN,EMN and EHN groups were increased?P<0.05?,which was statistically significant.No significant differences were found between the other groups.Compared with EP group,the expression of Lonp1 protein in ELN,EMN and EHN groups was increased?P<0.01?.Compared with the ELN group,the expression of Lonp1 protein in EMN and EHN groups was increased?P<0.01?.Compared with the EMN group,the expression of Lonp1 protein in the EHN group was decreased?P<0.01?.The results were statistically significant.There were no significant differences between the other groups.Compared with the EP group,the expression of PGC-1?protein in ELN and EMN groups was increased?P<0.01?.Compared with the EMN group,the expression of PGC-1?protein in the EHN group was decreased?P<0.01?.The results were statistically significant.There were no significant differences between the other groups.Compared with the EP group,the expression of NFAT5 protein in ELN,EMN and EHN groups was increased?P<0.01?.EHN histone expression was decreased compared with the ELN group?P<0.01?.Compared with the EMN group,EHN histone expression was decreased?P<0.01?.The results were statistically significant.Conclusion:The addition of nitrate for 6 days can increase the level of NO in cardiomyocytes.Although the total antioxidant capacity is not significantly increased,the antioxidant SOD increases and the peroxidation product MDA decreases.The myocardial PGC-1?,Lonp1 and NFAT5 in the nitrate exercise group were increased,while the low,medium concentrations were more effective.