Therapeutic approaches to protect the heart from ischemia/reperfusion (I/R) injury are an area of intense research, as myocardial infarction is a major cause of mortality and morbidity. Diterpenes are bioactive natural products with great therapeutic potential. In the present study, we have investigated the in vivo cardioprotective effects of a labdane diterpene (DT1) against cardiac I/R injury and the molecular mechanisms involved. DT1 attenuates post-ischemic injury via an AKT-dependent activation of HIF-1α, survival pathways and inhibition of NF-κB signaling. Myocardial infarction (MI) was induced in Wistar rats occluding the left coronary artery (LCA) for 30min followed by 72h reperfusion. DT1 (... More
Therapeutic approaches to protect the heart from ischemia/reperfusion (I/R) injury are an area of intense research, as myocardial infarction is a major cause of mortality and morbidity. Diterpenes are bioactive natural products with great therapeutic potential. In the present study, we have investigated the in vivo cardioprotective effects of a labdane diterpene (DT1) against cardiac I/R injury and the molecular mechanisms involved. DT1 attenuates post-ischemic injury via an AKT-dependent activation of HIF-1α, survival pathways and inhibition of NF-κB signaling. Myocardial infarction (MI) was induced in Wistar rats occluding the left coronary artery (LCA) for 30min followed by 72h reperfusion. DT1 (5mg/kg) was intravenously administered at reperfusion. In addition, we investigated the mechanisms of cardioprotection in the Langendorff-perfused model. Cardioprotection was observed when DT1 was administered after myocardial injury. The molecular mechanisms involved the activation of the survival pathway PDK-1, AKT and AMPK, a reduced phosphorylation of PKD1/2 and sustained HIF-1α activity, leading to increased expression of anti-apoptotic proteins and decreased caspase-3 activation. Pharmacological inhibition of AKT following MI and prior to DT1 challenge significantly decreased the cardioprotection afforded by DT1 therapy at reperfusion. Cardiac function after MI was significantly improved after DT1-treatment, as evidenced by hemodynamic recovery and decreased myocardial infarct size. These findings demonstrate an efficient in vivo cardioprotection by diterpene DT1 against I/R when administered at reperfusion, opening new therapeutic strategies as adjunctive therapy for the pharmacological management of I/R injury.Copyright 2014 Elsevier Inc. All rights reserved.
