Cardio-protection by Ginkgo biloba extract 50 in rats with acute myocardial infarction is related to Na⁺-Ca²⁺ exchanger.

Ginkgo biloba has been used for medical purposes for centuries in traditional Chinese medicine. Ginkgo biloba extract 50 (GBE50) is a new standardized GBE product that matches the standardized German product as EGb761. This paper is aimed at studying the cardio-protection effects of GBE50 Salvia miltiorrhiza on myocardial function, area at risk, myocardial ultra-structure, and expression of calcium handling proteins in rat ischemic myocardium. Myocardium ischemia was induced by the left anterior descending (LAD) coronary artery occlusion and myocardial function was recorded by a transducer advanced into the left ventricle on a computer system. In vitro myocardial infarction was measured by 2,3,5-triphenyltetrazolium chloride (TTC) and Evans blue staining of heart sections. Morphological change was evaluated by electric microscopy and Western blotting was used for protein expression. Hemodynamic experiments in vivo showed that postischemic cardiac contractile function was reduced in ischemic rats. Salvia miltiorrhiza (7.5 g/kg/d×7) and Ginkgo biloba extract 50 (GBE50) (100 mg/kg/d×7) improved post-schemic cardiac diastolic dysfunction while not affecting the systolic function. In hearts of GBE50 group and Salvia miltiorrhiza (SM) group, the area at risk was significantly reduced and myocardial structure was better-preserved. Moreover, Na⁺-Ca²⁺ exchanger (NCX) expression increase and sarcoplasmic reticulum Ca²⁺-ATPase 2 (SERCA2), LTCC, and ryanodine receptor 2 (RyR2) expression decreases were smaller than those in ischemia group. There was a significant difference between the GBE50 and ischemia group in NCX expression. GBE50 could improve recovery in contractile function and prevent myocardium from ischemia damage, which may be caused by attenuating the abnormal expression of NCX.