Prenatal cocaine exposure abolished ischemic preconditioning-induced protection in adult male rat hearts: role of PKCε

Abstract

Prenatal cocaine exposure in rats resulted in decreased PKCε protein expression in the heart of adult male but not female offspring. The present study determined its functional consequence of inhibiting cardioprotection mediated by ischemic preconditioning. Pregnant Sprague-Dawley rats were administered intraperitoneally saline or cocaine (30 mg·kg−1·day−1) from day 15 to day 21 of gestational age. Hearts were isolated from 3-mo-old offspring and were subjected to ischemia and reperfusion injury in a Langendorff preparation, with or without prior ischemic preconditioning. Preischemic values of left ventricular function were the same between the saline control and cocaine-treated animals. Ischemic preconditioning of two episodes of 5-min ischemia significantly decreased infarct size and enhanced postischemic functional recovery of the left ventricle in the saline control animals. This ischemic preconditioning was associated with increased phospho-PKCε, but not phospho-PKCδ, levels and was blocked by a PKCε translocation inhibitor peptide. Prenatal cocaine treatment abolished the ischemic preconditioning-mediated increase in phospho-PKCε and cardioprotection in the heart of male offspring. In contrast, the cardioprotective effect was fully maintained in female offspring that were exposed to cocaine before birth. The results suggest that prenatal cocaine exposure causes a sex-specific loss of cardioprotection by ischemic preconditioning in adult offspring, which is most likely due to fetal programming of PKCε gene repression, resulting in a downregulation of PKCε function in the heart of adult male offspring.