ABSTRACT
Objective Bone morphogenetic protein 4 ( BMP4) induces rat myocardial hypertrophy in H9c2 cells, but the spe-cific mechanism remains unclear .The study aimed to elucidate the role of autophagy in myocardial hypertrophy and its relationship with extracellular signal regulating kinase ( ERK1/2) signal transduction pathway . Methods H9c2 cardiomyocytes were randomly divided into 4 groups:control group, BMP4 group, BMP4+PD98059 (ERK1/2 signal pathway inhibitor) group and BMP4+3MA (autophagy inhibitor) group.With PD98059(50μmol/L) and 3MA(5mmol/L) blocking for 30min, BMP4 (50μg/L) were added.Expressions of tiny tube related proteins 1 light chain 3 (LC3) and p-ERK1/2 were detec-ted after culturing for 30min.48h later, measurements were made on cell surface area , average protein content and α-smooth muscle actin (α-SMA ) protein expression level .Cell morphology and size were measured respectively by inverted microscope and Image J software .Total protein content was detected by BCA , and western blot was used to measure the expressions of LC3, ERK1/2, p-ERK1/2 and α-SMA. Resul ts 30min later, the expressions of LC3 and p-ERK1/2 were significantly higher in BMP4 group than in control group [(1.54 ±0.05) vs (1.95 ±0.11),(0.94 ±0.04) vs (1.33 ± 0.06),P0.05). Conclusion Autophagy may participate in BMP4-induced rat myo-cardial hypertrophy in H9c2 cells through ERK1/2 signal transduction pathway .The clinical treatment of myocardial hypertrophy may benefit from the blocking of autophagy or ERK 1/2 signal transduction pathway .