akebia-saponin-d and Myocardial-Ischemia

Asperosaponin VI is a saponin of the medicinal herb Dipsacus asper (Xuduan), and no pharmacological activity has been reported yet. In this study, we investigated the anti-myocardial ischemia effects of Asperosaponin VI (ASA VI) both in vivo and in vitro. An animal model of myocardial ischemia(MI) injury was induced by coronary occlusion, pretreatment with ASA VI (10 and 20mg/kg, i.v.) could protect the heart from ischemia injury by decreasing the levels of creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), glutamic oxalacetic transaminase (GOT) and cardiac troponin T (cTnT) in serum, increasing the levels of catalase, glutathione peroxidase (GSH-Px) and superoxide dismutase (SOD) levels in heart, and decreasing that of malondialdehyde (MDA) level in acute MI rats. ASA VI also raised the activities of mitochondrial enzymes (succinate dehydrogenase (SDH), isocitrate dehydrogenase (ICDH), malate dehydrogenase (MDH) and alpha-ketoglutarate dehydrogenase (alpha-KGDH)) and those of adenosine triphosphate (ATP) content, but lowered Ca(2+) level. Electrocardiograph parameters and histopathological observations demonstrated the same protective effects. In vitro experiment, neonatal rat cardiomyocytes were incubated to test the direct cytoprotective effect of ASA VI against H(2)O(2) exposure. Pretreatment with ASA VI (30 and 60 microg/ml) prior to H(2)O(2) exposure increased cell viability and inhibited H(2)O(2)-induced reactive oxygen species increase. ASA VI (15, 30 and 60 microg/ml) also increased the activities of LDH in the cultured supernatant and SOD in cardiomyocytes, but decreased the cardiomyocytes MDA level. Our results suggested that ASA VI could provide significant cardioprotective effects against acute MI in rats. The mechanisms might be attributed to scavenging lipid peroxidation products and reactive oxygen species, increasing antioxidant defense enzymes and preventing mitochondrial damage.

Topics: Animals; Animals, Newborn; Cells, Cultured; Dipsacaceae; Electrocardiography; Heart; Hydrogen Peroxide; Male; Mitochondria; Myocardial Infarction; Myocardial Ischemia; Myocytes, Cardiac; Oxidative Stress; Rats; Rats, Sprague-Dawley; Saponins; Survival Rate; Triterpenes

Cardiomyocyte apoptosis plays a critical role in the progress of heart diseases. Asperosaponin VI (ASA VI), a triterpene saponin isolated from Dipsacus asper Wall, has shown cardioprotective effects in vivo. However, whether ASA VI has a protective effect against cardiomyocyte apoptosis is poorly understood. The present study was aimed to investigate the cardioprotective role of ASA VI and the underlying mechanisms in hypoxia-induced cardiomyocyte apoptosis. Cardiomyocytes were exposed to hypoxic condition for 6 h and then cell viability markedly decreased, lactate dehydrogenase (LDH) and creatine phosphokinase (CK) activities in the culture supernatant significantly increased. Hypoxia-activated apoptosis were confirmed by Hoechst 33258 nuclear staining and Annexin V-FITC staining. These changes were associated with the decrease of the Bcl-2/Bax ratio, active caspase-3 expression, phosphorylations of Akt and cAMP response element-binding protein (CREB). Moreover, ASA VI significantly attenuated increased LDH and CK activities, and increased cell viability in hypoxia treated myocytes in a dose-dependent fashion. Hoechst 33258 nuclear staining and Annexin V-FITC staining observations demonstrated the same protective effects. ASA VI treatment inhibited apoptosis in hypoxia-induced cardiomyocyte by increasing the Bcl-2/Bax ratio and decreasing active caspase-3 expression, as well as enhancing of p-Akt and p-CREB. Furthermore, the protective effects of ASA VI were prevented by phosphatidylinositol-3-kinase (PI3K) inhibitor LY294002 treatment. In consequence, we demonstrated that ASA VI had protective effect against hypoxia-induced cardiomyocytes apoptosis probably by activating the PI3K/Akt and CREB pathways.

Topics: Animals; Apoptosis; Apoptosis Regulatory Proteins; Cardiotonic Agents; Cell Hypoxia; Cell Line; Cell Nucleus; Cell Survival; Chromones; Creatine Kinase; Cyclic AMP Response Element-Binding Protein; Enzyme Inhibitors; L-Lactate Dehydrogenase; Morpholines; Myocardial Ischemia; Myocytes, Cardiac; Phosphoinositide-3 Kinase Inhibitors; Phosphorylation; Rats; Saponins; Signal Transduction