cytochrome-c-t and leonurine

Apoptosis of cardiomyocytes induced by oxidative stress play a critical role in cardiac dysfunction associated with ventricular remodeling and heart failure. We recently reported that leonurine attenuated hypoxia-induced cardiomyocyte damage. In this study, we investigated the mechanism of leonurine (originally from Herba leonuri but we synthesized it chemically it as also called SCM-198) (H₂O₂)-induced rat embryonic heart-derived H9c2 cells from apoptosis. Exposing H9c2 cells to H₂O₂ significantly decreased cell viability, and this was attenuated by pretreatment with leonurine for 4 h in a concentration-dependent manner. Meanwhile, leonurine was found to reduce intracellular reactive oxygen species (ROS) generation in H₂O₂-stimulated cell. Moreover, H9c2 cells stimulated by H₂O₂ was accompanied with apparent apoptotic characteristics, including fragmentation of DNA, apoptotic body formation, release of cytochrome c, translocation of Bax to mitochondria, loss of mitochondrial membrane potential (ΔΨ(m)) and activation of caspase 3. Furthermore, H₂O₂ also induced rapid and significant phosphorylation of the c-Jun-N-terminal kinase 1/2 (JNK1/2), which was inhibited SP600125 (a JNK1/2 inhibitor). All of these events were attenuated by leonurine pretreatment. Taken together, these results demonstrated that leonurine could protect H9c2 cells from H₂O₂-induced apoptosis via modulation of mitochondrial dysfunction associated with blocking the activation of JNK1/2.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Cell Line; Cell Survival; Cytochromes c; DNA Fragmentation; Gallic Acid; Membrane Potential, Mitochondrial; Mitochondria; Mitogen-Activated Protein Kinase 8; Mitogen-Activated Protein Kinase 9; Myocytes, Cardiac; Oxidative Stress; Peroxides; Phytotherapy; Poly (ADP-Ribose) Polymerase-1; Poly(ADP-ribose) Polymerases; Rats; Reactive Oxygen Species

Ischemic brain is particularly susceptible to free radicals mediated secondary neuronal damage, especially mitochondrial dysfunctions. Chinese Herbal Medicine with antioxidant properties is believed to have potential therapeutic effect. Leonurine, an alkaloid present in Herba Leonuri (HL), has shown biological effects such as antioxidant, anticoagulant, anti-apoptosis and protection against ischemic heart disease. In this study, neuroprotective effects of leonurine against cerebral ischemia/reperfusion-induced mitochondrial dysfunctions in cortex were evaluated. We used transient rat middle cerebral artery occlusion (MCAO) model of brain ischemia. The rats were treated with their respective treatments for 1 week prior to the MCAO. We found that leonurine significantly improved neurological outcome and reduced ischemia/reperfusion (I/R)-induced cerebral infarction 24 h after MCAO. Leonurine decreased reactive oxygen species (ROS) level in mitochondria isolated from ischemic cortex, which was increased by MCAO. Terminal deoxyuridine triphosphate (dUTP) Nick-End Labeling (TUNEL) staining showed anti-apoptotic effect of leonurine on ischemic cortex. Western blot analysis showed a marked decrease in the expression of Bax and an increase of Bcl-2 as a result of leonurine treatment. The attenuation of mitochondrial membrane swelling, restore of mitochondrial membrane potential and content of cytochrome c (Cyt-C) in mitochondria isolated from ischemic cortex could also be observed in leonurine treated group. The findings of this study suggest that leonurine has promising therapeutic effect for ischemic stroke treatment through antioxidant and anti-apoptotic mechanisms.

Topics: Animals; Antioxidants; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Brain Ischemia; Cerebral Cortex; Cerebral Infarction; Cytochromes c; Disease Models, Animal; Drugs, Chinese Herbal; Gallic Acid; In Situ Nick-End Labeling; Leonurus; Male; Membrane Potential, Mitochondrial; Mitochondria; Mitochondrial Membranes; Neuroprotective Agents; Oxidative Stress; Phytotherapy; Proto-Oncogene Proteins c-bcl-2; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reperfusion Injury

In the present study, we examined the ability of a chemically synthesized compound based on the structure of leonurine, a phytochemical component of Herba leonuri, to protect H9c2 rat ventricular cells from apoptosis induced by hypoxia and serum deprivation, as a model of ischemia. The results revealed a concentration-dependent increase in cell viability associated with leonurine treatment, accompanied by a consistent decline in lactate dehydrogenase leakage into the culture medium. The fraction of annexin V-fluorescein isothiocyanate-positive cells was increased by hypoxia but reduced by leonurine. These changes were associated with increased expression of the antiapoptotic gene, Bcl-2, and reduced expression of the proapoptotic gene, Bax. Leonurine also reduced the cytosolic Ca overload induced by hypoxia. These results suggest that leonurine elicits potent cardioprotective effects in H9c2 cells, and these effects may be mediated by inhibition of intracellular Ca overload and apoptosis during hypoxia.

Topics: Animals; Apoptosis; bcl-2-Associated X Protein; Blotting, Western; Calcium; Cardiotonic Agents; Cell Hypoxia; Cell Line; Cell Survival; Cytochromes c; Cytosol; Drugs, Chinese Herbal; Flow Cytometry; Gallic Acid; Heart Ventricles; Microscopy, Fluorescence; Mitochondria, Heart; Molecular Structure; Myocytes, Cardiac; Proto-Oncogene Proteins c-bcl-2; Rats; Superoxide Dismutase