Potential cardioprotective role of menaquinone-4 against cardiac ischemia-reperfusion injury.

Myocardial infarction is among the leading causes of mortality. Menaquinone-4 (MK-4), a vitamin K2 analog, might play a role in rescuing cardiac ischemia/reperfusion (I/R) injury. This work aimed to discover the potential cardioprotective role of MK-4 against myocardial I/R injury in rats. Thirty-two rats were categorized into three groups: (I/R) control Group: subjected to I/R protocol (received vehicle); MK-4 preconditioning group: MK-4 infusion for 20 minutes before the I/R protocol; MK-4 postconditioning group: MK-4 infusion for 20 minutes at the start of the reperfusion phase. The hearts were placed in the Langendorff apparatus, and the left ventricular developed pressure (LVDP), heart rate (HR), + (LV dP/dt) max , - (LV dP/dt) max, and Tau were calculated. The necrotic mass was determined by staining it with nitro blue tetrazolium. Creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and C- reactive protein (CRP), as well as cardiac superoxide dismutase (SOD), nitric oxide (NOx), malondialdehyde (MDA), and glutathione (GSH) levels, were all evaluated. MK-4 postconditioning significantly reduced myocardial infarct size, increased LVDP, + (LV dp/dt) max, - (LV dp/dt) max, and HR, reduced Tau, CK-MB, LDH, CRP, IL-6, TNF-α, MDA and NOx levels, and increased SOD activity whereas no significant difference in the GSH level was detected. In conclusion, these data imply that MK-4 may protect the heart from the consequences of I/R.