The Role Of Short-chain Acyl-CoA Dehydrogenase In Heart Failure

Objective:Short-chain acyl-CoA dehydrogenase(SCAD)is a key enzyme for fatty acid beta oxidation,closely related to heart energy metabolism.However,the changes of its relative expression level in heart failure and its regulation on energy metabolism are still unclear.In order to further clarify the role of SCAD in heart failure,we established different rat models of heart failure and explored the changes of SCAD expression,and observed the effects of adenovirus-mediated SCAD overexpression on apoptotic cardiomyocyte model and myocardial infarction-induced heart failure rat model.Explored the changes of SCAD expression in patients with heart failure,Method:1.To establish 20-month-old spontaneously hypertensive rat model of chronic heart failure.Echocardiography,blood pressure,left ventricular mass index,Masson trichrome staining,DHE staining and transmission electron microscopy were used to evaluate the changes of Cardiology and ultrastructure;mitochondrial JC-1 method andmitochondrial membrane swelling were used to detect mitochondrial function;TUNEL staining were used to detect cardiomyocyte apoptosis;RT-PCR and Western Blot were used to detect the expression of SCAD and PPARa,apoptotic protein Caspase-3,Bcl-2,Bax;Detected SCAD activity,ATP activity and the contents of free fatty acids in myocardium and serum.To analyze the apoptosis of myocardium in heart failure after myocardial infarction.To study the changes of SCAD in heart failure after myocardial infarction and the relationship between SCAD and heart energy metabolism.2.The left anterior descending coronary artery ligation(LAD)was used to establish heart failure model in SD rats to further study the changes of SCAD in heart failure induced by myocardial infarction and its relationship with cardiac energy metabolism.At the same time,under the intervention of exercise rehabilitation training,the changing trend of SCAD was studied to determine whether SCAD has positive protective effect in heart failure.Echocardiography,blood pressure,Masson trichrome staining,DHE staining and transmission electron microscopy were used to evaluate the changes of cardiology and ultrastructure;mitochondrial JC-1 method and mitochondrial membrane swelling were used to detect mitochondrial function;TUNEL staining were used to detect cardiomyocyte apoptosis;RT-PCR and Western Blot were used to detect the expression of SCAD and PPARα,apoptotic protein Caspase-3,Bcl-2,Bax;Detected SCAD activity,ATP activity and the contents of free fatty acids in myocardium and serum to analysis the changes of myocardial apoptosis and energy metabolism.3.By constructing adenovirus vector of SCAD gene,the best transfection titer was found to make SCAD overexpress in cardiac myocytes.Adenovirus-mediated SCAD overexpression pretreatment was performed before myocardial cell apoptosis model was established by tert-butyl hydroperoxide(tBHP).Cell proliferation and viability were detected by CCK-8.Apoptosis was detected by Hochtest 33258/PI.The expression of SCAD,caspase-3,Bcl-2 and Bax was also observed by RT-PCR and Western Blot.SCAD activity,ATP content,free fatty acid content in myocardium and serum were detected.To analysis the relationship of SCAD with myocardial apoptosis and energy metabolism.4.The rat model of overexpression was established by multi-point injection of adenovirus into the ventricular wall.The expression of SCAD in the heart was detected by Western Blot to determine the duration of overexpression.The effects of SCAD overexpression on cardiac pathology after LAD were evaluated by echocardiography,blood pressure and Masson trichrome staining.The expressions of SCAD,apoptotic protein Bcl-2 and Bax were detected by RT-PCR and Western Blot.The SCAD activity,content of ATP,content of free fatty acids in myocardium and serum were also measured.Analysed the changes of myocardialapoptosis and energy metabolism to confirm the relationship between SCAD and heart failure.5.The changes of SCAD in normal and heart failure patients were observed by immunofluorescence.To explore whether SCAD has the same trend at the human level,and further determine the possibility of SCAD as a new target for the treatment of heart failure.Result:1.Echocardiographic results showed that 20-month-old spontaneously hypertensive rats could successfully reproduce the rat model of chronic heart failure.The indexes of heart function in heart failure rats were obviously unbalanced.The persistent hypertensive state in SHR rats decreased significantly in the late stage of heart failure,which may be related to the decline of systolic and diastolic function of heart failure.There were obvious myocardial fibrosis,myocardial apoptosis and left ventricular pathological remodeling in chronic heart failure.The ultrastructure of myocardial cells was obviously damaged.Mitochondrial swelling,decreased mitochondrial membrane potential,excessive deposition of reactive oxygen species and excessive autophagy accelerated the process of heart failure.At the same time,we found that the expression of SCAD was negatively regulated with the progression of heart failure,the activity of SCAD was significantly decreased,the free fatty acids were deposited in myocardium and serum,and the ATPcontent was significantly decreased.2.Echocardiographic results showed that the rat model of heart failure after myocardial infarction was successfully reproduced 4 weeks after LAD,and followed by swimming intervention lasting 10 weeks.The changes of cardiology and ultrastructure,expression of SCAD and PPARα,and fatty acid metabolism in simply LAD rats were consistent with the results of chronic heart failure rats in the previous chapter.After10 weeks of aerobic exercise intervention,the process of heart failure in LAD+swim rats was significantly inhibited.At the same time,we found that the expression of SCAD and PPARα was significantly increased,and the impairment of cardiac energy metabolism was significantly improved.3.Adenovirus-mediated SCAD overexpression pretreatment can improve apoptosis induced by tBHP,and improve myocardial energy metabolism.4.Adenovirus-mediated overexpression of SCAD in the heart can improve the cardiology related to heart failure after LAD,and improve the energy metabolism disorder of the heart.5.The results of SCAD immunofluorescence showed that the expression of SCAD in heart tissues of patients with heart failure was consistent with that of apoptotic cardiomyocytes and rats with heart failure,and had a negative regulatory effect on heart failure.Conclusion:SCAD is closely related to heart failure and negatively regulated by heart failure.As a key enzyme in the energy supply of heart fatty acid metabolism,increasing the expression of SCAD can inhibit the process of heart failure,which may be related to the intervention of energy metabolism and mitochondrial apoptotic pathway.SCAD may become a new target for the treatment of heart failure.