| Objective Chronic heart failure is a disease that develops to the terminal stage of various heart diseases.Venous congestion and insufficiency of blood supply in the arterial system are the main pathological and physiological changes.The abnormal calcium ion circulation may be one of the reasons for its development in cardiac myocytes in the cause of heart failure.Calcium ion cycles are mainly involved in the release,recovery and storage.Many related molecules are involved in their changes.In this experiment,the rat model of chronic heart failure was established.Discussing on the expression of RyR2,calstabin2,Triadin and Junctin in cardiac myocytes.In order to obtain its mechanism in heart failure and provide molecular basis theory for the prevention and clinical intervention.Methods?1?Grouping:30 adult male SD rats were selected and divided into 15 heart failure groups and 15 sham groups randomly.?2?Modeling:Rats in heart failure group were subjected to permanent ligation of the left anterior descending coronary artery;In the sham operation group,the left anterior descending coronary artery was only used for threading and no ligation was performed.?3?Measuring heart function:After 28 days of free feeding,the carotid intubation was used and the BL-420 system was used to detect the functional indicators of the phase,and the success of the model was determined.?4?Isolated cardiomyocytes:Cardiomyocytes were isolated by enzymolysis.?5?Detection of Ca2+by fluorescent staining:Fluo-5N loaded ventricular myocytes directly recorded the changes of calcium content in sarcoplasmic reticulum;Indirect recording of calcium ion concentration in sarcoplasmic reticulum by Caffeine-induced Ca2+transients.?6?Protein expression:The membrane protein of two groups of rat myocardium was extracted and the levels of related proteins was measured by Western-blot.?7?Statistical analysis:SPSS17.0 statistics software is used in data processing.All data are presented as mean±SD.The average number between the two groups was compared with the t-test,and the difference was significant?P-values of<0.05?.Results?1?There was a significant descend in the left ventricular end-diastolic pressure?LVEDP?in sham rats?4.68±1.21 mmHg,n=15?compared with HF rats?8.61±2.14 mmHg,P<0.01?.There was a significant raise in the maximal change of systolic pressure over time(dp/dtmax)in control group rats?4,677.65±230.64 mmHg/s,n=15?compared with HF group rats?2,350.18±172.44 mmHg/s,n=15,P<0.01?and there was a significant reduce in the maximum change in the rate of relaxation over time(dp/dtmin)in HF rats?-1,435.26±132.15mmHg/s,n=15?compared with control group rats?-3,012.32±230.12 mmHg/s,n=15,P<0.01?.In addition to there was a significant add in heart weight?HW?divided by body weight?BW?in HF rats?6.82±0.31,n=15?compared with sham rats?3.45±0.42,n=15,P<0.01?.?2?The amplitude of Ca2+transients was also declined in HF group.There was a significant raise in spatial averages??F/F0?of Caffeine-induced Ca2+transients in sham group rats?54.72±2.12n=16,P<0.01?compared with HF group rats?15.45±1.05?.?3?The expression of Calstabin2was significantly reduced in HF rat compared with sham group?n=6,P<0.01?.The expression of RyR2 was no obvious change in HF rat compared with sham group?n=6,P<0.01?.The expression of Triadin and Junctin were significantly reduced in HF rat compared with sham group?n=6,P<0.01?Conclusion There was no change in the expression of RyR2,and the expression of its attachment protein Calstabin2 was reduced,which may result in the heart to release too much calcium through RyR2 during the diastolic and lead to the reduction of systolic calcium release,bringing about the reduction of myocardial contractility.Down-regulation of Triandin and Junctin could contribute to HF;The decreased expression of Triadin and Junctin leads to the weakening of the ability of sarcoplasmic reticulum to Ca2+and the leakage of Ca2+in the ventricular diastole,which may be one of the reason of chronic heart failure. |
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