Improvement of contractile function in isolated cardiomyocytes from ischemia-reperfusion rats by ginkgolide B pretreatment.

Ginkgo biloba extract is an important natural product for treatment of cerebral and cardiovascular diseases, whereas ginkgolide B (GB) is a main component of it. Its effects on ischemic heart and ventricular contractile function in Sprague-Dawley male rats are unclear yet. In the present study, we investigated the function of isolated hearts subjected to ischemia-reperfusion (IR) with or without GB pretreatment by using Millar transducer instruments. We also tested the left ventricular cardiomyocyte shortening amplitude after IR with different concentrations of GB pretreatment for 0.1, 1.0, 2.0, 5.0, and 10.0 microM. The infarct size was tested by triphenyltetrazolium chloride. The release of lactate dehydrogenase (LDH) in the coronary effluent was determined with LDH kit. The expressions of Bcl-2 and Bax were assessed by Western blotting. We found that GB improved the function of left ventricle from IR injury and decreased infarct size and the release of LDH. The cardiomyocyte shortening amplitude depended on different concentrations of GB, which increased significantly at 2.0 microM GB (P < 0.01). The expression of protein Bcl-2 was upregulated by GB and the ratio of Bax to Bcl-2 was decreased by GB. Our results showed that GB can partly prevent IR injury in rat heart.