The aim of this study was to evaluate the cardioprotective effect of
pinacidil postconditioning on rat hearts with transient
hypoxia and reperfusion. An acute myocardial
anoxia-reperfusion rat model was created by ligating coronary arteries for 10 min and subsequent reperfusion for 60 min. Twenty-four rats in 4 groups received different treatments: normal hearts as control (N = 6),
anoxia-reperfusion (A/R) only (N = 6),
pinacidil postconditioning (N = 6), and
pinacidil plus
adenosine triphosphate-sensitive
potassium channel inhibitors (
glibenclamide) (N = 6). The kinetic parameters and electrophysiological properties, including early apoptosis
protein expression changes of Bax, Bcl-2, and FN were examined using the isolated perfusion and patch-clamp technique and immunohistochemistry. The left ventricular systolic pressure and maximum -dp/dt in A/R groups were significantly higher than those in the control group (P < 0.05). The left ventricular developing pressure, maximum +dp/dt, and heart rate in the A/R group were slightly decreased. The
pinacidil-postconditioned group has better cardiac function recovery after
ischemia/reperfusion than the A/R group (P < 0.01). In addition, using the patch-clamp technique, the mean open time and conductance values are significantly higher in the
pinacidil postconditioning group, compared with those in the A/R group. The expression of apoptosis
proteins (Bax, FN) increased during A/R, while Bcl-2
protein expression decreased. A significant difference was found in the
pinacidil treatment group relative to the A/R group.
Pinacidil postconditioning can exert cardioprotective effects on A/R-injured rat hearts, which may indicate a potential application of
pinacidil postconditioning to protect A/R-injured hearts.