| Objective: Atrial fibrillation(AF)is a kind of arrhythmia,the occurrence of atrial fibrillation development mechanism has been the focus in the field of cardiovascular research field,and atrial fibrillation is a important cause of high morbidity and high mortality.With population aging atrial fibrillation has become an important medical issue that threatens public health.Although a large number of studies have been conducted to further understand the pathogenesis of atrial fibrillation,the exact pathogenesis of this disease remains unclear.Atrial remodeling is one of the most important path physiological mechanisms in AF development,and fiber is a major marker for atrial reconstruction.Atrial fibrosis mainly involves the following path physiological mechanisms: Renin-angiotensin-aldosterone system(RAAS),TGF-beta 1 pathway and inflammation.Myocardial fibroblasts(Cardiac fibroblasts,CFs)take part in the development of atrial fibrosis trial myofibroblast proliferation and its activation.It can also be transformed into muscle fibroblast phenotype,which are capable of synthesizing and secreting synthesize and secrete a large number of collagen protein,thereby promoting atrial remodeling induced myocardial fibrosis.The activation and proliferation of myocardial fibroblasts are critical in myocardial fibrosis are a type of secretary cells,which can secrete inflammatory factors that further promote fibroblasts proliferation,differentiation and secretion to form a positive feedback,in the progress of atrial fibrosis.TGF-beta 1 is a regulatory protein super family that has many members of related cytokines,which is of great significance in the process of tissue repair,cell growth and the development of fibrosis.For most of the normal form of inactive potential,the secretion of TGF-beta 1 which involved in regulating tissue repair cell growth condition and in the process of the formation of extracellular matrix.TGF-beta 1 can promote the synthesis of type I collagen fiber in myocardial fibroblasts,which induces myocardial fibrosis.The Cell adhesion molecule 1,a new tumor suppressor gene located in the human chromosome 11q23.2,confirms that CADM1 is a tumor suppressor gene.Participate in cytoskeleton to build and maintain the stability of cell adhesion function,induction of apoptosis,inhibiting tumor cell proliferation,so when the expression cut will lead to the occurrence and metastasis of tumor invasion.Signal transduction and transcriptional activation factor(STAT)is a kind of important cell involved in cell signal transcription factors.Interferon,interleukin,growth factors and other exogenous signal stimulation can activate STAT3 signaling pathways,and regulate the expression of downstream target genes,involved in cell proliferation,differentiation,apoptosis and biological processes,such as immunity.Further studies have found that CADM1 inhibited the development of squalors cell carcinoma by reducing signaling pathway protein STAT3 activity.Therefore,it is necessary to explore whether CADM1 can inhibit the development of atrial reconstruction by lowering the activity of signaling pathway protein STAT3.The study shows that micro-RNAs play an important role in myocardial reconstruction and myocardial fibroblast proliferation.This experiment aims to detect mirco RNA-21 and its regulation expression in atrial tissue and cardiac fibroblasts,to observe the mirco RNA-21 mimics and mirco RNA-21 inhibitors on rat myocardial fibroblasts proliferation effects of activation,and to explore the mirco RNA-21 may through mediated CADM1/STAT3 molecular mechanism fibrillation.Methods: Collected in October 2014 to December 2015 in the second affiliated hospital of Anhui medical university,with 30 cases of rheumatic heart valve replacement surgery patients,ruled out with high blood pressure,diabetes,angina pectoris and chronic renal insufficiency.According to the AF diagnostic criteria,the AF group and the sinus rhythm group,namely AF group and SR group,were obtained from each group of myocardial tissue specimens.The method of the hypodermic injection of isopropyl hydrochloride in the lower abdomen was used to replicate the model of the myocardial fibrosis model of the Sprague-Darley rats.The SD rats without specific pathogens were compared The rats in the experimental group were injected with the hypodermic injection of ISO,and the blank group of rats gave the same amount of saline injection under the lower abdomen,and the heart was taken out and the specimens were obtained.SD rats completely soaked in 75% ethanol for disinfection,sterilization time for 1 min,then,in advance of uv lamp to illuminate aseptic laboratory bench,adopt the method of differential sticking wall myocardial cells,remove sidewall is needed for the experiment of rat cardiac fibroblasts,the inverted microscope to observe cells with fiber typical form,can be identified as myocardial fibroblasts.After adding 5 ml medium,continue to develop in the incubator to the state of cell fusion is 80% ~ 90% of the time for cells to extend operation,extend the 3 consecutive after cultured cells for subsequent related experiments.Liposome with Lipofectamine TM2000 to rat cardiac fibroblasts transfixion Reagent mirco RNA-21 mimics and inhibitors and their negative control,48 h after testing the indicators.HE and Masson staining method were used to detect myocardial fibrosis and collagen volume fraction(CVF)in myocardial tissue.The expression levels of mirco RNA-21,CADM1 and STAT3 m RNA were detected by real-time fluorescence quantitative PCR(qrt-PCR)for mirco RNA-21 control groups.The expression of CADM1 and STAT3 proteins in microrna-21 mimics and control groups were determined by Western blot.The expression levels of CADM1 and STAT3 protein in microrna-21 mimics and control groups were determined by Western blot method.MTT assay was used to detect the effects of microrna-21 and inhibitors on the activation and proliferation of myocardial fibroblasts.Results: HE staining showed that there was significant growth of collagen fibers in the myocardial interstitial in the AF group.Masson staining showed that the degree of fibrosis in AF group was more serious and the volume fraction of CVF was significantly higher.Compared with the SR group,qrt-PCR detected the expression of micro RNA-21 and STAT3 in atrial fibrillation,while CADM1 expression decreased.Western blot was used to detect the expression of STAT3 expression in atrial fibrillation,while CADM1 expression decreased.After the myocardial fibroblasts of micro RNA-21 mimics were transected,compared with the negative control group,qrt-PCR detected micro RNA-21 high expression in myocardial fibroblasts in rats,and the expression of STAT3 expression increased and CADM1 expression decreased.MTT detection showed that myocardial fibroblast proliferation activity of micro RNA-21 mimics was significantly enhanced.After the myocardial fibroblasts in rats were transected,the negative control group,qrt-PCR detected the decrease of micro RNA-21 in the myocardial fibroblasts in rats,the expression of STAT3 decreased and CADM1 expression increased.Conclusion: Atrial fibrillation patients with myocardial tissue fibrosis lesions,high expression of mirco RNA-21 in atrial organization through CADM1 / STAT3 signaling pathway to reduce the expression of STAT3,to participate in the occurrence of myocardial fibrosis development.Micro RNA-21 mimics has been significantly higher,and micro RNA-21 inhibitors significantly inhibited the activity of myocardial fibroblast proliferation,Which suggests that micro RNAs-21 May is a very important part in atrial fibrillation mechanism of molecular,mi RNA-21 is myocardial fibroblasts proliferation potential targeted molecular activation benefit for clinical intervention and prevent the happening of the atrial fibrillation myocardial fibrosis development provides new ideas. |
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