Abstract: Objective: Platelet apoptosis plays an important role in the development and progression of cardiovascular diseases. Curcumin (Cur), a polyphenol compound enriched in the rhizomes of turmeric (Curcuma longa), exerts a wide range of biological activities. Whether Cur acts on platelet apoptosis has not been reported. We therefore sought to investigate the effects of Cur on platelet apoptosis induced by H2O2 as well as to clarify the underlying mechanisms in vitro. Methods: Gel-filtered human platelets were pre-incubated with different concentrations of Cur (0, 1, 10 and 100 μmol/L) for 30 min, followed by intervention with H2O2 (100 μmol/L) for 60 min. The levels of platelet phosphatidylserine (PS) exposure and mitochondrial membrane potential (ΔΨm) depolarization were determined by flow cytometry. Enzyme linked immunosorbent assay was used to measure caspase-3 and caspase-9 activation, and reactive oxygen species (ROS) and superoxide generation. The expression of Bax, Bak and cytochrome c were evaluated by Western blot. Results: H2O2-induced platelet PS exposure and ΔΨm depolarization were significantly attenuated by 10、100 μmol/L Cur treatment when compared with the control group (P < 0.05). Moreover, Cur significantly down-regulated Bax, Bak and cytochrome c expression in platelets treated with H2O2 (P < 0.05). H2O2-induced platelet caspase-3 and caspase-9 activation were significantly inhibited by 10、100 μmol/L Cur (P < 0.05). Additionally, the levels of intracellular total ROS and superoxide were significantly increased in H2O2-treated platelets, which were attenuated by Cur intervention (P < 0.05). Conclusion: Cur can inhibit H2O2-induced platelet apoptosis in vitro.

Key words: curcumin; platelet; apoptosis; hydrogen peroxide; oxidative stress; cardiovascular diseases