Notch1 signaling activation protected myocardium against hypoxia injury via reducing programmed cell death.

Programmed cell death plays an important role in cardio protection, and Notch1 was an important factor related to programmed cell death. The role of Notch1 on ischemia myocardium remains unclear.H9C2 myocardial cells were cultured with routine medium, transfected with Notch1 over expression plasmid, Notch1-siRNA-overexpression plasmid and vehicle plasmid for further hypoxic experiment. Condition of hypoxic experiment was 1% oxygen centration and culturing for 12hours, then the cell proliferation activity and apoptosis rate was assessed by MTS kit and flow cytometry, respectively. The expressions of Caspase-3, Caspase-9 and Bcl-2 were determined by RT-qPCR and Western Blot, respectively. Compared with normoxia treatment, hypoxia could decrease H9C2 cell proliferation activity as well as Bcl-2 mRNA expression, and increase cell apoptosis rate as well as Caspase-3 and Caspase-9 mRNA expression. Notch1 activation could increase proliferation activity as well as Bcl-2 mRNA expression, while decrease apoptosis rate as well as Caspase-3 and Caspase-9 mRNA expression. Compared with Notch1 activation H9C2 cells, the opposite effect on programmed cell death was observed in cells with Notch1-siRNA-overexpression plasmid. Targeted activation of Notch1 gene to reduce hypoxia-induced programmed cell death in myocardial cells via up-regulating the expression of Caspase-3 and Caspase-9 and inhibiting the expression of Bcl-2.