| Objective:Myocardial infarction (MI), which is very harmful to human health and life, has a high mortality rate. MI is very harmful to human health and life of cardiovascular disease, a high mortality rate. Left ventricular function and structure have certain changes after MI, that is the structure remodeling of ventricular, including myocardial cells breaking down, infarction area disproportionate thinner and expansion, ventricular enlargement with decreased cardiac function, and results in the deadly arrhythmia and heart failure, even cardiac death. Whether the atrial structure remodeling happened at the same as ventricular structure remodeling after MI, and if the atrial structure remodeling is the base of the origin and development of atrial fibrillation, has yet to be confirmed. Recently, a study showed that the patients of MI, especially with left ventricular systolic dysfunction, had the highest risk of new atrial fibrillation in two months, which incidence was about four times previously reported, and atrial fibrillation induced by MI had a higher risk of death. So we should be attention for the atrial fibrillation induced by MI, and clear the mechanism to heighten preventing of atrial fibrillation. The present study showed that the occurrence and maintain mechanism of AF including atrial structure remodeling, electrical remodeling, nerve remodeling, and whether atrial fibrillation after MI is exactly have structure remodeling, and how to prevent the remodeling to reduce the occurrence of AF after MI is the key. In recent years, the prevention and treatment effect of cardiovascular disease of statins have aroused more and more people’s attention, and the effects on the prevention and control of arrhythmia become the focus, which restrain the structure reconstruction was one of the mechanisms of prevention for arrhythmia, whether statins can inhibit atrial structure reconstruction after MI to prevent atrial arrhythmias especially the occurrence of atrial fibrillation needs to be further research.Research Aims:First make MI rabbit model, then apply Rosuvastatin for eight weeks, by detecting structure and morphology of myocardium cells, the distribution of intercellular substance and collagen fiber, inner diameter of left atrial(LAD), the changes of expression of collagen and collagen I, to observe the influence of Rosuvastatin on structure remodeling of MI rabbit.Methods:1. Make MI rabbit model by ligating anterior descending artery after opening chest;2. Divide alive rabbits into:the group of myocardial infarction (MI, n=7), small dose Rosuvastatin group (Rs,2.5mg/(kg.d), n=7), large doses of Rosuvastatin (R1,5mg/(kg.d), n=8), and set sham group (S, n=8);3. Examine the left ventricular ejection fraction and LAD,LVSD,LVDD by echocardiographic after8weeks;4. The heart and left ventricular mass was weighed;5. Observe morphological changes of left atrium organization by HE and Massion dyeing methods;6. Detect left atrium collagen content changes by application ultraviolet spectrophotometer;7. Determine collagen I protein content by application western blot methods.Results: 1. After eight weeks, LAD, collagen content of left atrium, and the expression of collagen I of MI group were more significantly increased than control group, Rs group and R1group (P<0.05);2. After eight weeks, LVEF of MI group was more significantly decreased than control group, Rs group and R1group (P<0.05);3. There were no significantly statistically differences between Rs group and Rl group on LAD, left atrial collagen content, the expression of collagen I and LVEF;Conclusion and Significance:1. Statins had the improvement effect on atrial structure remodeling after MI;2. The statins can suppress atrial structure remodeling after MI to minimize the incidence of atrial arrhythmias especially cardiovascular events such as atrial fibrillation;... |
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