| BackgroundThe birth prevalence of CHD is9.3per1,000live births in Asia,8.2per1,000livebirths in Europe and6.9per1,000live births in North America.The5most commonsubtypes of CHD (per1,000live births) were: VSD,2.62; ASD,1.64; PDA,0.87; PS,0.50; TOF,0.34; In these subtypes, VSD, ASD, PDA are most likely to formation ofPAH. In order to effective treatment of this complication, we need to know thepathogenesis of CHD-PAH.Pulmonary hypertension is caused by functional and structural change in thepulmonary vasculature, leading to increase pulmonary vascular resistance. Theprocess of pulmonary vascular remodeling is accompanied by endothelial dysfunction,activation of fibroblasts and smooth muscle cell.In2008Evian conference, the“Evianclassification” made a great change of the PAH classification.Thisclassification attempted to create categories of PH thatshared pathologic andclinical features as well as similar therapeutic options. In the first groups, pulmonaryarterial hypertension (PAH) include idiopathic and heritable PAH, Drug and toxininduced PAH, Associated with PAH, persistent pulmonary hypertension of thenewborn3.CHD-PAH is congenital heart disease associated with pulmonary arteryhypertension. The pathological change is characterized by pulmonary vascularremodeling. The high prevalence makes it necessary to study its pathogenesis.Vascular remodeling is an integral pathological process central to pulmonaryarterial hypertension. The complex interplay between distinct cell populations in thevessel wall following shear stress leads to inflammation, cellular dysfunction,pro-growth signals in the endothelial cells compartment and the acquisition of asynthetic phenotype. Although the signals forvascular remodeling are diverse indifferent pathological contexts, endothelial cellproliferation and migration areconsistently observed. It is therefore critical to elucidate keymechanisms central tothese processes. MiRNAs are small non-coding RNA that has thecapacity to regulatemany genes, pathways and complex biological networks within cells, actingeitheralone or in concert with one another. In diseases such as cancer and cardiac disease,therole of miRNA in disease pathogenesis has been documented in detail. In contrast,despite a greatdeal of interest in miRNA, relatively few studies have directly assessedthe role of miRNA in pulmonary vascular remodeling. The potential for modulation of-4- miRNA to achieve therapeutic benefits inthis setting is attractive. Here, we focus onthe role of vascular shear stress change on miRNA in endothelial cell andremodelingassociated with shear stress changes as well in the development of vascularremodeling associated with the development of pulmonary arterial hypertension.In thepresent study, the expression patterns of miR-19a were investigatedin normal and leftto right shunt rat’s modellung tissue. The effects of miR-19a in modulating cellproliferation, apoptosis and endothelial cell markers in SD rat pulmonary endothelialcells (PAECs) were investigated in vitro. MiR-19aexpression in rats PAECs wascorrelated with an increase in right ventricular systolic pressure and decrease inBMPR2. Increase of miR-19a levels in PAECs causes increased proliferation andreduced apoptosis and these effects were reversed by thedown expression of miR-19a.MiR-19a overexpressiondown regulated BMPR2expression, which is key a factor inPAH development. These results suggest that miR-19a is apotential regulator ofproliferation, apoptosis and differentiation of PAECs, and that it could be used as anovel treatmentstrategy in PAH.ObjectiveThis research is to study the possible regulate effect of miRNA on left to rightshunt PAH rat model, and it also could provide theoretical basis for new treatmenttarget for CHD-PAH clinically.MethodSD rats wererandomly divided into four groups: surgery groups, T1and T2(puncture the abdominal aorta and inferior vena); normal control groups, T3and T4(open the abdominal cavity, but don’t puncture the abdominal aorta and inferior vena).After4weeks and8weeks, test the hemodynamic datarespectively. After thehemodynamic data test, executed the animal and keeped the right middle lung lobe insuitable ways.Define the pathological changes with immunohistochemical stainingand test the protein with western-blotting. Detect the miR-19a in the lung tissue; usethe same way to make out the change in rat’s transfectional pulmonary endothelialcells.Results1.Compare to the control groups, the experimental groups’ pulmonary pressurehave significant increase (p＜0.05). The mean pulmonary artery pressure of T1is31.3±2.9mmHg, the mean pulmonary artery pressure of T3is15.5±1.08mmHg, the mean pulmonary artery pressure of T2is40.8±2.6mmHg, the mean pulmonary arterypressure of T4is16.0±0.94mmHg.2.Compare to the control groups, the pulmonary endothelium and middle of theexperimental groups have obvious proliferation; the middle collagen fibershyperplasia obviously in experimental groups (p＜0.05). Immunohistochemicalstaining showed that BMPR2expression reduced significantly in the experimentalgroups(p＜0.05), the result of the western-blotting is the same asimmunohistochemical staining result. qRT-PCR result showed that miR-19a increasedozens of times in lung tissue of experimental groups compare to the control groups(p＜0.05). We have successfully cultured SD rats’ endothelial cells in vivio, theimmunohistochemical staining positive rate of factor VⅡI is95%.3. The SD rat endothelial cells were transfected miR-19a with lip2000and mimics.The miR-19a increased hundreds of times to thousands of times after24hours oftransfection. Western-blotting result show that BMPR2in transfection groupdecreased significantly (p＜0.05).Conclusions1. Hemodynamic changes in rat pulmonary artery can lead to increased expressionof miR-19a, increased expression of miR-19a and hemodynamic changes are closelyrelated.2. The hemodynamic changes lead to decrease in rat lung tissue expression ofBMPR2, pulmonary degree of remodeling and BMPR2expression was negativelycorrelated.3. Cell experiments found that miR-19a overexpression can lead to reducedBMPR2expression, and thus we can see the target genes of miR-19a is BMPR2.Hemodynamic changes lead to increased expression of miR-19a, miR-19a expressiondecreased expression is closely related with the BMPR2, there is reason to believethat in the progress of pulmonary artery remodeling induced by hemodynamicchanges, miR-19a play an important role. |
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