[Effects of p66shc adapter protein and estrogen on cardiomyocyte apoptosis induced by angiotensin II].

Objective: To explore the role of p66shc in cardiomyocyte apoptosis induced by angiotensin (Ang) II and the effect of estrogen pretreatment.

Methods: Neonatal rat cardiomyocytes were randomly divided into five groups: normal control, 10(-11) mol/L Ang II, 10(-9) mol/L Ang II, 10(-7) mol/L Ang II, and 10(-7) mol/L Ang II + estrogen treated groups. The cell viability was measured by MTT. The level of reactive oxygen species (ROS) and cell apoptosis rate were measured by flow cytometry. Mitochondrial membrane potential (MMP) was detected using a fluorescence microplate reader, and the protein expression of phosphorylated and total p66shc were detected using Western blot.

Results: With the increase of Ang II concentrations, cell viabilities and MMP levels decreased, whereas, the levels of ROS and cell apoptosis rates increased (P < 0.05). Pretreatment with estrogen significantly attenuated the cardiomyocyte injury induced by Ang II (P < 0.05). The protein expression of phosphorylated p66shc in the whole cell lysates and total p66shc in the mitochondria increased in a dose-dependent manner when cardiomyocytes were exposed to Ang II (P < 0.05). Pretreatment with estrogen significantly down-regulated the protein expression of phosphorylated p66shc in the whole cell lysates and total p66shc in the mitochondria (P < 0.05).

Conclusion: p66shc is involved in cardiomyocyte apoptosis induced by Ang II, and estrogen could attenuate Ang II induced cardiomyocyte injury through down-regulating the protein expression of p66shc.