TNF-α Mediated That LPS-induced Cardiomyocyte Injury Up-regulated 14-3-3γ Isoform

Objective: To study the effect of 14-3-3 protein andγisoform in LPS-induced cardiomyocyte injury and the role of TNF-αat celluar level.Methods: (1)cultured primary neonatal SD rat cardiomyocytes were used to be treated with LPS for 12 hours at the 4th day and were randomly divided into for four groups ,separately was control group (C), LPS1mg/l groups (LPS1);LPS 10mg/l groups (LPS2); LPS 100mg/l groups(LPS3). At the end of LPS experiment, cardiocytes beating rate, cell viability and the activity of LDH in culture were measured, furthermore, the expression of 14-3-3γmRNA,TNF-αmRNA,14-3-3 protein,and TNF-αprotein were measured by RT-PCR ,western blotting techniques,ELISA, respectively.(2)we can use cultured primary neonatal SD rat cardiomyocytes to be treated with TNF-αat the 4th day and randomly divide the cells into five groups .separately was control group (C), TNF-α100IU/ml groups for 12h (TNF1); TNF-α300IU/ml groups for 12h (TNF2); TNF-α1000IU/ml groups for 12h (TNF3) ; TNF-α3000IU/ml groups for 12h (TNF4). Results: (1)LPS model :the beating rate was significantly slower among all different dose groups compared with that of control group(p<0.05),except LPS1(p﹥0.05);and, the cell viability was significantly lower than control (p<0.05 or p<0.01) ; LDH activity of different doses groups was significantly increased when compared with that of control group (p<0.05 or p<0.01).so,the beating rate of ventricular myocytes and the cell viability of ventricular myocytes was decreased with dose larger, the LDH activity was increased with dose larger.The expression of TNF-αmRNA and protein immulated by LPS was significantly increased when compared with that of control group(p<0.01); the alike 14-3-3γmRNA change happended to expression of 14-3-3 protein that,increased ahead then decreased behind when dose larger.but, not at the equal pace with the change of 14-3-3γmRNA.(2) TNF-αmodels:the expression of 14-3-3 protein andγmRNA increased ahead then decreased behind ,it suggested that the alike 14-3-3 protein andγmRNA changes of LPS model happended to TNF-αmodel. Conclusion:It is verified that 14-3-3γmRNA and protein had a basic expression in cardiocytes under normal condition,and it was increased after LPS added in. LPS stimulation can increase the endogenous expression of TNF-α.Exogenous TNF-αcan up-regulate 14-3-3γmRNA.So,we can conclude that TNF-α,partly,if not all, participates upregulation process of 14-3-3 in LPS injury.