Effects of Rho Kinase Inhibition on Cardioprotection

Rho Kinase (Rho-K) has been implicated in the pathophysiology of many deleterious conditions and its inhibition was shown to ameliorate these compromising effects. It is unclear; however, whether inhibition of Rho-K would decrease infarct size in hearts after ischemia/reperfusion. Adult ICR mice were randomized to 1 of 4 treatments: saline, fasudil (Rho-K inhibitor (10 mg/kg i.p.), Fasudil+L-NAME (Nitric Oxide synthase inhibitor, 15 mg/kg), and L-NAME. Hearts were isolated, perfused in Langendorff mode and subjected to 30 min stabilization before 30 min ischemia and 60 min reperfusion. Left ventricular (LV) function was monitored. Hearts were stained and infarct size measured. Fasudil reduced infarct size as compared with control hearts; however, this protective effect was abolished by L-NAME. LV function mirrored these trends. The loss of cardioprotection after L-NAME administration indicates that cardioprotection by Rho-K inhibition is mediated through nitric oxide-dependent pathway. Furthermore, Fasudil administration at and throughout reperfusion showed similar cardioprotection