Necrostatin: A potentially novel cardioprotective agent?

Background Necrostatin-1 ( Nec-1), a small tryptophanbased molecule, was recently reported to protect the cerebral cortex against ischemia-reperfusion (I/R) injury. We investigated the actions of Nec-1 and its so-called inactive analog, Nec-1i, in the setting of myocardial I/R injury. Materials and methods The actions of Nec-1 and Nec-1i were examined in cultured C2C12 and H9c2 myocytes, cardiomyocytes isolated from male Sprague-Dawley rats, Langendorff isolated perfused C57Bl/6J mouse hearts and an in vivo open-chest C57Bl/6J mouse heart model. Results Nec-1 at 30 mu M and 100 M ( but not 100 mu M Nec-1i) reduced peroxide- induced cell death in C2C12 cells from 51.2 +/- 1.1% (control) to 26.3 +/- 2.9% ( p< 0.01 vs control) and 17.8 +/- 0.9% ( p< 0.001), respectively. With H9c2 cells cell death was also reduced from 73.0 +/- 0.4% ( control) to 56.7 +/- 0% ( 30 mu M Nec-1, p< 0.05) and 45.4 +/- 3.3% ( 100 mu M Nec-1, p< 0.01). In the isolated perfused heart Nec-1 ( 30 mu M) reduced infarct size ( calculated as a percentage of the risk area) from 48.0 +/- 2.0% ( control) to 32.1 +/- 5.4% ( p< 0.05). Nec-1i ( 30 mu M) also reduced infarct size ( 32.9 +/- 5.1%, p< 0.05). In anesthetized C57Bl/6J mice Nec-1 (1.65 mg/kg), given intraperitoneally to coincide with reperfusion following left anterior descending artery ligation ( 30 min), also reduced infarct size from 45.3 +/- 5.1% (control) to 26.6 +/- 4.0% ( p< 0.05), whilst Nec-1i ( 1.74 mg/kg) was ineffective (37.8 +/- 6.0%). Stimulus- induced opening of the mitochondrial permeability transition pore ( MPTP) in rat cardiomyocytes, as reflected by the time until mitochondrial depolarisation, was unaffected by Nec-1 or Nec-1i at 30 mu M but increased at 100 mu M i.e. 91%(p< 0.05 vs control) and 152% ( p< 0.001) for Nec-1 and Nec-1i, respectively. Conclusion This is the first study to demonstrate that necrostatins inhibit myocardial cell death and reduce infarct size, possibly via a mechanism independent of the MPTP.