The Altered Gene Expression Of MHC,MLC2,MLCK In Human Atrial Fibrillation

Objective To investigate the gene expression of myosin heavy chain (αMHC,βMHC),myosin light chain 2(MLC2A,MLC2V)and myosin light chain kinase(MLCK) in human atrial fibrillation (AF). Methods The mRNA amount ofαMHC,βMHC,MLC2A,MLC2V,MLCK mRNA genes was measured by reverse transcription-polymerse chain reaction (RT-PCR) and normalized to the mRNA content ofβactin or GAPDH in 59 patients with rheumatic heart disease underwent valve replacements. Subject with sinus rhythm (SR) were considered as control group. the protein amount ofβMHC was measured by Immuno - histochemistry Results compared with that in patients with SR ,the content (3.00±1.42 vs 2.06±0.82, P<0.01)and the proportion (34.25±12.54% vs 25.63±9.75%, P<0.01)in total MHC ofβMHC mRNA was increased significantly in patients with chronic atrial fibrillation(CAF) and remained stable in patients with paroxysmal atrial fibrillation (PAF)(P>0.05);the content of MLC2V was increased significantly in patients with CAF (P<0.05) and remained stable in patients with PAF(P>0.05); there were no significant changes in mRNA content ofαMHC,MLC2A,MLCK,MHC(α+β)及MHC+MLC2 in all groups(P>0.05); the protein content ofβMHC was increased significantly in patients with CAF (85360787.400±22188581.0404 VS 57349942.727±9101232.6904,p<0.001)and remained stable in patients with PAF(P>0.05); Conclusion The up-regulation of the gene expression ofβMHC and altered expression in total MHC (α+β) may serve as the molecular basis of the transform fromαMHC toβMHC in patients with CAF, which may be one of the mechanisms in the AF contractile remodeling.