Effects Of Nitrate Of Supplement On Myocardial Sarcoplasmic Reticulum Ca²⁺Channel Protein In Acute Exercise Rats

Objective:This study was designed to observe the effect of supplementation of different doses of exogenous inorganic nitrate on the calcium plasmin protein in rat cardiac sarcoplasmic reticulum induced by one-time exhaustive exercise.By glucose regulated protein 78?GRP78?protein expression to judge the sarcoplasmic reticulum stress state.By the expressions of the Sarcoplasmic/endoplasmic reticulum calcium ATPase 2?SERCA2?,phospholamban?PLN?,ryanodine receptors 2?RyR2?,which located at myocardial sarcoplasmic reticulum,analysis of the effect of exogenous inorganic nitrate on the stable expression of myocardial sarcoplasmic reticulum calcium channel protein.Methods:40 SD male rats were randomly divided into 5 groups,quiet group?CP?,exercise group?EP?,exercise low dose group?ELN?,exercise middle dose group?EMN?,and exercise high dose group?EHN?,eight in each group.After 3 days of adaptive feeding,the ELN,EMN and EHN groups were fed with sodium nitrate solution at doses of 0.3,0.7 and 1.0 mmol/kg BW/D,respectively.CP and EP groups were intragastrically administered with the same volume of normal saline daily for 6 days.All of the exercise group conducted a one-time overload training after the end of the intragastrically administered on the 6th.Five groups of rats were anesthetized immediately after exhaustion,measuring the changes in serum and myocardial tissue.Statistical analysis was performed using independent sample T-test and one-way ANOVA.Results:?1?The expression of GRP78 in EP is higher than that in CP?P<0.01?.Compared with the CP,the SERCA2,PLN expressions are decreased in the EP?P<0.01?.?2?The concentration of[NO₂^-]in serum is higher in ELN than EP?P<0.05?.The concentration in EMN is higher than that in EP?P<0.01?and ELN?P<0.05?.The concentration of EHN is higher than in EP,ELN,EMN?P<0.01?.To the concentration of NO,the ELN is higher than EP?P<0.01?.The EMN is higher than EP and ELN?P<0.01?.The EHN is higher than EP and ELN?P<0.01?.There are no significant differences in myocardial NO concentration and NOS activity between CP and EP.The NO content in ELN/EMN/EHN compared with EP increased and the differences are statistically significant.The differences of NOS activity in each group are not statistically significant.?3?The expression of GRP78 in ELN is lower than that in EP?P<0.01?,EMN is lower than that in EP?P<0.01?and lower than ELN?P<0.05?,EHN is lower than EP?P<0.01?.The expression of SERCA2 in ELN is higher than EP?P<0.01?and higher than EMN,EHN?P<0.05?,EHN expression is higher than EP?P<0.05?.To RyR2 or PLN,EP,ELN,EMN or EHN differences between the groups are not statistically significant.Conclusion:?1?Six-day inorganic nitrate supplementation could improve the expression of SERCA2 in myocardial,but no significant effect on RyR2 with no change of the activity of the NOS enzyme in myocardial.?2?Six-day inorganic nitrate supplementation can alleviate myocardial sarcoplasmic reticulum stress induced by one-time high-intensity exercise.Relatively high and low concentrations of nitrate supplementation,medium dose concentration is the best to improve myocardial sarcoplasmic reticulum stress induced by one-time exhaustive exercise.