The Effects And Receptor Mechanism Of Prostaglandin E2on Hypertrophy In H9c2Cardica Cells

ObjectiveThe goals of this study are to explore the effects of prostaglandin E2(PGE2) on H9c2cardiomyocyte hypertrophy and the dose-effectrelationship, to investigate the role of prostaglandin E2receptors (EPs) inH9c2cardiomyocyte hypertrophy induced by PGE2, and to enhance thetheoretic foundation in searching for possible targets of inhibitingmyocardial hypertrophy.MethodsThe experiment includes two sections. The first section aims to explorethe effects of prostaglandin E2on H9c2cardiomyocyte hypertrophy. Thesecond section aims to investigate the role of prostaglandin E2receptors inH9c2cardiomyocyte hypertrophy induced by PGE2.1. In the first section, H9c2cardiac cells were divided randomly intocontrol group (group C1), low dose PGE2group (group D1), middle dosePGE2group (group D2) and high dose PGE2group (group D3). The finalconcentrations of all the four groups were0μmol/L,0.1μmol/L,1μmol/L and10μmol/L, respectively.2. In the second section, H9c2cardiac cells were divided randomly intocontrol group (group C2), PGE2group, EP1and EP2receptors antagonistgroup (group A), EP4receptor antagonist group (group B), EP1and EP2receptors antagonist combined with EP4receptor antagonist group (groupE). PGE2group received PGE2. Group A received PGE2and AH6809(EP1and EP2receptors antagonist). Group B received PGE2andGW627368X (EP4receptor antagonist). Group E received PGE2andAH6809, GW627368X. Here, the final concentration of PGE2in eachinvolved group was1μmol/L, and the final concentrations of AH6809andGW627368X in each involved group were both10μmol/L.3. Cells of all groups were cultured for48hours, and then cellmorphology and cell volume were observed by fluorescent microscope.Cell diameter was calculated by the Image J medical image analysis system.Total protein content of the cells was measured with the BCA method.Expression levels of atrial natriuretic peptide (ANP) mRNA and brainnatriuretic peptide (BNP) mRNA in cells were analyzed with the RT-PCRtechnique.Results1. The cell diameter and the total protein content of cardiac cells withthe stimulated by PGE2significantly increased. Meanwhile, the celldiameter and the total protein content of cardiac cells significantly increased according with the upregulation of PGE2doses. In the secondpart, the cell diameter and the total protein content of cardiac cells in all theother groups significantly increased than that in control group. Furthermore,compared with PGE2group, the cell diameter and the total protein contentof cardiac cells decreased in group B and group E. The result of EP1andEP2receptors antagonist group was not significantly different from that ofPGE2group.2. With the help of fluorescent microscope, an obvious aggrandizementof the cell volume with the stimulation by different doses of PGE2wasobserved. EP4receptor antagonist could lessen the augmentation of cellsinduced by PGE2, rather than EP1and EP2receptors antagonist. However,the cell volumes of cardiac cells still increased significantly in group B andgroup E than that in control group.3. The expression levels of ANP mRNA and BNP mRNA in cardiaccells upregulated with the feeding of1μmol/L and10μmol/L doses ofPGE2. Compared with control group, there was an increasing of ANPmRNA and BNP mRNA expression levels. Compared with PGE2group,EP4receptor antagonist downregulated the expression levels.Conclusion1. PGE2induces myocardial hypertrophy of the cultured H9c2cardiaccells in a dose-dependent manner.1μmol/L of PGE2is sufficient tostimulate pathological myocardial hypertrophy. 2. PGE2induces cardiomyocyte hypertrophy, and upregulates theexpression levels of ANP mRNA and BNP mRNA mediated by EP4, ratherthan EP1and EP2. However, besides EP4, there are also other receptors tomediate the cardiomyocyte hypertrophy induced by PGE2. EP3is one ofthe most possible potential effective receptors.3. Inhibition of PGE2or antagonize PGE2receptor EP4is expected tobe new targets to control myocardial hypertrophy in clinical.