Resveratrol protects rabbit ventricular myocytes against oxidative stress-induced arrhythmogenic activity and Ca ²⁺ overload

Abstract

Aim:

To investigate whether resveratrol suppressed oxidative stress-induced arrhythmogenic activity and Ca ²⁺ overload in ventricular myocytes and to explore the underlying mechanisms.

Methods:

Hydrogen peroxide (H ₂O ₂, 200 μmol/L)) was used to induce oxidative stress in rabbit ventricular myocytes. Cell shortening and calcium transients were simultaneously recorded to detect arrhythmogenic activity and to measure intracellular Ca ²⁺ ([Ca ²⁺] _i). Ca ²⁺/calmodulin-dependent protein kinases II (CaMKII) activity was measured using a CaMKII kit or Western blotting analysis. Voltage-activated Na ⁺ and Ca ²⁺ currents were examined using whole-cell recording in myocytes.

Results:

H ₂O ₂ markedly prolonged Ca ²⁺ transient duration (CaTD), and induced early afterdepolarization (EAD)-like and delayed afterdepolarization (DAD)-like arrhythmogenic activity in myocytes paced at 0.16 Hz or 0.5 Hz. Application of resveratrol (30 or 50 μmol/L) dose-dependently suppressed H ₂O ₂-induced EAD-like arrhythmogenic activity and attenuated CaTD prolongation. Co-treatment with resveratrol (50 μmol/L) effectively prevented both EAD-like and DAD-like arrhythmogenic activity induced by H ₂O ₂. In addition, resveratrol markedly blunted H ₂O ₂-induced diastolic [Ca ²⁺] _i accumulation and prevented the myocytes from developing hypercontracture. In whole-cell recording studies, H ₂O ₂ significantly enhanced the late Na ⁺ current ( I _Na,L) and L-type Ca ²⁺ current ( I _Ca,L) in myocytes, which were dramatically suppressed or prevented by resveratrol. Furthermore, H ₂O ₂-induced ROS production and CaMKII activation were significantly prevented by resveratrol.

Conclusion:

Resveratrol protects ventricular myocytes against oxidative stress-induced arrhythmogenic activity and Ca ²⁺ overload through inhibition of I _Na,L/ I _Ca,L, reduction of ROS generation, and prevention of CaMKII activation.