| Objective Atrial fibrillation is the most common chronic and recurrent arrhythmia in clinical work practice.The prevalence and morbidity of atrial fibrillation gradually increase with age.Atrial fibrillation leads to myocardial fibrosis and is an important feature of myocardial remodeling.DNA methylation has been shown to be involved in the process of myocardial remodeling.DNA methyltransferase 3A is closely related to myocardial fibrosis.In patients with atrial fibrillation,it may affect the development of the disease.In this paper,DNMT3 A protein was used as a research point to investigate the correlation between DNMT3 A protein and homocysteine in patients with rheumatic valvular heart disease and atrial fibrillation by measuring the changes in tissue samples.Methods Clinically,22 patients with related cases were collected.The patients undergoing valve replacement surgery in the Department of Cardiothoracic Surgery of the Second Affiliated Hospital of Anhui Medical University for rheumatic heart disease were treated with blood specimens taken before surgery and atrial ear tissue harvested during surgery.According to atrial fibrillation Definitions 22 specimens were divided into sinus rhythm(SR)group and atrial fibrillation group.The two groups of patients did not have hypertension,diabetes,severe liver and kidney disease,mental illness and malignant tumors and other major diseases that may affect the test results.Cardiac function was measured by routine electrocardiogram and echocardiography.The expression of DNMT3 A protein and type 1 collagen(Col1A1)in myocardial tissue was determined by Western Blotting and immunohistochemistry.The protein content of DNMT3 A in myocardial tissue was determined.Enzyme-linked immunosorbent assay(ELISA)assay.ELISA and biochemical enzyme cycle method for determination of Hcy content in serum.A statistical analysis of the two sets of data measured was performed.Results The ECG report suggested that compared with the sinus rhythm group,the normal P wave of the electrocardiogram disappeared in the atrial fibrillation group,f wave appeared,and the QRS wave spacing was different.The echocardiographic report suggested that the atrial fibrillation group compared with the sinus rhythm group.Left ventricular ejection fraction(LVEF)is lower,ejection efficiency is worse,and indicators reflecting changes in heart size such as left ventricular end-diastolic diameter(LVDD),left atrial diameter(LAD),and right atrial diameter(RAD)are significantly increased.The results of Western Blotting showed that the expression of DNMT3 A protein and Col1A1 protein in atrial fibrillation group was higher than that in sinus rhythm group.The results of ELISA showed that the content of DNMT3 A in myocardial tissue of atrial fibrillation group was significantly higher than that of sinus rhythm group.The results of immunohistochemistry showed the myocardial remodeling was significantly increased in the atrial fibrillation group.The expression of DNMT3 A protein and Col1A1 protein was significantly higher than that in the sinus rhythm group.The results of ELISA and enzyme cycling showed that the serum Hcy content of patients with atrial fibrillation increased significantly.There was a positive correlation between DNMT3 A protein and Hcy expression in patients with atrial fibrillation(r=0.573,P<0.01).Conclusion DNA methyltransferase 3A and serum homocysteine levels increase significantly in patients with rheumatic valvular heart disease and atrial fibrillation;through correlation analysis,there is a positive correlation between the expression levels of the two.These indicate that abnormal expression of DNA methyltransferase3 A protein in patients with atrial fibrillation may be the molecular basis for the maintenance of atrial fibrillation.Increased expression of DNA methyltransferase 3A and homocysteine in patients with rheumatic valvular heart disease complicated withatrial fibrillation may be involved in the development of rheumatic valvular heart disease with atrial fibrillation. |
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