AIMTo observe the injured effect of homocysteine (HCY) on cardiomyocytes and investigate its signal transduction mechanism as well as the key regulatory link.

METHODSCardiomyocytes were isolated from neonatal Wistar rats. After incubation with HCY, the survival rate of cardiomyocytes was determined by trypan blue stained assay, while the apoptosis rate was measured by TUNEL and FCM. Western blot and EMSA were used to tested ERK2 protein phosphorylation and NF-kappaB active expression in cardiomyocytes, respectively.

RESULTSThe survival rate of cardiomyocytes treated with HCY was reduced significantly in dose- and time- dependent manner. It was found that 10(-3) mol/L HCY could increase the apoptosis rate of cardiomyocytes to the peak (7.65%) at 4 h stress. Several HCY levels revealed the strong inhibitory effect on ERK2 protein phosphorylation, especially, 10(-3) mol/L HCY decreased the level of active ERK2 expression to 3.04% of control at 4 h (P < 0.01). NF-kappaB activation was also inhibited significantly by several HCY level for different time in cardiomyocytes.

CONCLUSIONHCY plays an important role in injury of cardiomyocytes and apoptosis is a form of HCY-induced injury to cardiomyocytes. HCY can block ERK2 protein phosphorylation and NF-kappaB activation, which contribute to the injury of cardiomyocytes.