| Objective：microRNAs is closely related to the occurrence of atrialfibrillation (AF), miRNA-101(miR-101)has been reported to involve in theoccurrence and maintaining of atrial fibrillation. Bioinformatics predict L-typecalcium channel beta2subunits (CACNB2) may be target gene of miR-101,and abnormal calcium ion current in the myocardial cell is the important causeof atrial fibrillation, miR-101do or do not play an important role in AF byregulating the CACNB2, we did not find in the reports. Na+-Ca2+exchanger(NCX) is one of the widely distributed on the myocardial cell membranetransporters, by through exchanging3Na+to Ca2+to maintain the calciumbalance of intracellular. The maintenance of NCX on myocardial cell calciumhomeostasis plays an important role in the calcium balance, the abnormalexpression of NCX is also one of the important mechanism on AF. Thisexperiment will study the express changes of miR-101, CACNB2, NCX bydetecting the right auricle organization of patients with rheumatic heart diseaseon atrial fibrillation, preliminary discussing the correlation of miR-101and the disorder of calcium ion current in myocardial cell, expounding the possiblemechanisium of miR-101in the occurrence and maintaining on AF.Methods：The right atrial tissue was collected from Rheumatic heart valvereplacement patients,and the number of the patient were49for Chronic AF,45for normal Sinus rhythm(SR). We use Real-time quantative PCR(RT-PCR) tomeasure the abundance of microRNA-101、CACNB2and NCX by2-△△ctmethod.Extracted total protein so that we could use western blot to measure theexpression of CACNB2and NCX proteins of the right atrial tissue in twogroups by a semi-quantative Method.Results:（1）Compared with SR group, the age、sexuality、way ofoperations were no marked difference in AF group. Echocardiography promptthat inner diameter of left atrium in AF group is obviously lager than SRgroup(57.0±9.1vs46.7±4.5，P<0.05）。（2）Compared with SR group, Theexpression of microRNA-101was significantly down-regulated (P <0.05) in AFgroup,（0.6157±0.1749vs2.2900±0.3992，P<0.05）.（3）Compared with SRgroup, the expression of mRNA and protein of CACNB2and NCX weresignificantly up-regulated (P <0.05) in AF group. Compared with SR group, theexpression of mRNA of CACNB2was significantly up-regulated（1.9783±0.3231vs0.7215±0.4021，P<0.05）in AF group. Compared with SRgroup, the expression of mRNA of NCX was significantly up-regulated（1.8317±0.3015vs0.5978±0.3121，P<0.05）in AF group. Compared with SRgroup, the expression of protein of CACNB2was significantly up-regulated（1.35±0.20vs1.07±0.23，P<0.05）in AF group. the expression of protein ofNCX was significantly up-regulated （1.42±0.13vs1.03±0.26，P<0.05）in AFgroup. Conclusions:（1） The occurrence of AF may associate with thedown-regulation of microRNA-101；（2）the expression of mRNA and protein ofCACNB2was significantly up-regulated (P <0.05) in AF group,correspond tothe physical regulation of microRNA-101,suggesting that CACNB2may be thetarget gene of microRNA-101;(3) miR-101may negative regulateCACNB2,suggesting miR-101may participate in AF through causing theturbulance of calsium currunt..(4) the expression of mRNA and protein of NCXwere significantly up-regulated (P <0.05) in AF group suggesting that may existCa2+overload in myocardial cells.further indicating that miR-101may lead toAF through initiate Ca2+overload in myocardial cells. |
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