Diosgenin attenuates inflammatory response induced by myocardial reperfusion injury: role of mitochondrial ATP-sensitive potassium channels

Reperfusion injury is one of the main reasons of cardiac disease morbidity. Phytopharmaceuticals are gaining importance in modern medicine of cardioprotection because of their multiplex capacity. The aim of this study was to investigate the effect of diosgenin on the inflammatory response induced by myocardial ischemia and reperfusion injury and the role of mitochondrial ATP-sensitive potassium (mitoKATP) channels in this regard. Wistar rats (250-300 g) were used in this study. The Langendorff-perfused hearts of animals were subjected to a 30-min global ischemia followed by a 90-min reperfusion. The lactate dehydrogenase (LDH) release was measured by spectrophotometry. The levels of inflammatory mediators tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1 beta), and IL-6 in the supernatant of heart's left ventricle were measured using an enzyme-linked immunosorbent assay rat specific ELISA kit. The LDH release into the coronary effluent during reperfusion was significantly decreased, and cardiac contractility significantly improved by diosgenin preadministration as compared with those of control or Cremophor-EL (solvent of diosgenin) groups (398 +/- 48 vs. 665 +/- 65 or 650 +/- 73 ml/min) (P<0.01). Administration of diosgenin before the main ischemia significantly reduced the levels of IL-6 (P<0.05), IL-1 beta, and TNF-alpha (P<0.01) in the reperfusion phase of diosgenin-treated hearts as compared with untreated control hearts. Inhibition of mitoKATP channels by 5-hydroxydecanoate significantly reverses the cardioprotective effects of diosgenin (P<0.05). The findings of the present study indicate that preconditioning with diosgenin may induce cardioprotective effect against reperfusion injury through reducing the production of inflammatory mediators and activating the mitoKATP channels.