Paeoniflorin inhibits doxorubicin-induced cardiomyocyte apoptosis by downregulating microRNA-1 expression.

Doxorubicin (DOX) is an effective anthracycline anti-tumor antibiotic. Because of its cardiotoxicity, the clinical application of DOX is limited. Paeoniflorin (PEF), a monoterpene glucoside extracted from the dry root of Paeonia, is reported to exert multiple beneficial effects on the cardiovascular system. The present study was designed to explore the protective effect of PEF against DOX-induced cardiomyocyte apoptosis and the underlying mechanism. In cultured H9c2 cells, PEF (100 µmol/l) was added for 2 h prior to exposure to DOX (5 µmol/l) for 24 h. Cell viability, creatine kinase activity, cardiomyocyte apoptosis, intracellular reactive oxygen species (ROS) levels, and the expression of microRNA-1 (miR-1) and B-cell lymphoma 2 (Bcl-2) were measured following treatment with PEF and/or DOX. The results showed that treatment with DOX notably induced cardiomyocyte apoptosis, concomitantly with enhanced ROS generation, upregulated miR-1 expression and downregulated Bcl-2 expression. These effects of DOX were significantly inhibited by pretreatment of the cells with PEF. These results suggest that the inhibitory effect of PEF on DOX-induced cardiomyocyte apoptosis may be associated with downregulation of miR-1 expression via a reduction in ROS generation.

Picroside â ¡ inhibits hypoxia/reoxygenation-induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in reactive oxygen species production.

Reactive oxygen species (ROS)­induced mitochondrial dysfunction plays an important role in cardiomyocyte apoptosis during myocardial ischemia/reperfusion (I/R) injury. Picroside Ⅱ, isolated from Picrorhiza scrophulariiflora Pennell (Scrophulariaceae), has been reported to protect cardiomyocytes from hypoxia/reoxygenation (H/R)­induced apoptosis, but the exact mechanism is not fully clear. The aim of the present study was to explore the protective effects of picroside Ⅱ on H/R­induced cardiomyocyte apoptosis and the underlying mechanism. In the H9c2 rat cardiomyocyte cell line, picroside Ⅱ (100 µg/ml) was added for 48 h prior to H/R. The results showed that picroside Ⅱ markedly inhibited H/R­induced cardiomyocyte apoptosis. In addition, picroside Ⅱ was also able to decrease the opening degree of mitochondrial permeability transition pore (mPTP), increase the mitochondrial membrane potential, inhibit cytochrome c release from mitochondria to cytosol and downregulate caspase­3 expression and activity concomitantly with the decreased ROS production. These results suggested that picroside Ⅱ inhibited H/R­induced cardiomyocyte apoptosis by ameliorating mitochondrial function through a mechanism involving a decrease in ROS production.

Inhibitory effects of paeoniflorin on lysophosphatidylcholine-induced inflammatory factor production in human umbilical vein endothelial cells.

Lysophosphatidylcholine (LPC) plays an important role in atherosclerosis through initiation of endothelial inflammation response. Paeoniflorin (PEF), isolated from the dry root of Paeonia, has been reported to exert an anti-inflammatory effect, but the exact mechanism is not fully understood. The aim of this study was to investigate the inhibitory effects of PEF on LPC-induced inflammatory factor production and the underlying mechanisms. In human umbilical vein endothelial cells (HUVECs), different concentrations (1, 10 or 100 µmol/l) of PEF were added 2 h prior to exposure to LPC (10 mg/l) for 24 h. The results showed that PEF significantly inhibited LPC-induced inflammatory factor production. In addition, PEF was also able to suppress the enhanced high mobility group box-1 (HMGB1) expression and release, upregulated expression of receptor for advanced glycation end product (RAGE), Toll-like receptor (TLR)-2 and TLR-4, and increased nuclear factor-κB (NF-κB) activity induced by LPC. Our results suggest that PEF suppresses LPC-induced inflammatory factor production through inhibition of the HMGB1-RAGE/TLR-2/TLR-4-NF-κB pathway.

Paeoniflorin protects myocardial cell from doxorubicin-induced apoptosis through inhibition of NADPH oxidase.

Increased intracellular reactive oxygen species (ROS) are involved in doxorubicin (DOX)-induced myocardial cell apoptosis, and paeoniflorin (PEF) has been shown to exert an antioxidant effect. The aim of the present study was to explore the protective effect of PEF on DOX-induced myocardial cell apoptosis and the underlying mechanisms. In cultured H9c2 cells, different concentrations (1, 10, or 100 µmol/L) of PEF was added for 2 h prior to exposure to DOX (5 µmol/L) for 24 h. Cell apoptosis was evaluated by hoechst 33342 staining, and caspase-3 expression and activity. The mRNA and protein expression of NADPH oxidase (NOX) 2 and NOX4 was determined by real-time polymerase chain reaction and Western blot, respectively. Intracellular ROS and NOX activity were measured by assay kit. The results showed that DOX significantly increased myocardial cell apoptosis, increased caspase-3 expression and activity concomitantly with enhanced ROS production, and increased NOX2, NOX4 mRNA and protein expression, and NOX activity. These effects were remarkably inhibited by pretreatment of PEF. Our results suggested that PEF has a protective effect against DOX-induced myocardial cell apoptosis through a mechanism involving a decrease in ROS production by inhibition of NOX2, NOX4 expression, and NOX activity.

[Effects of acrolein on apoptosis of H9c2 cardiacmyocytes with hypoxia/reoxygenation injury].

OBJECTIVE: To determine the cytotoxic effects of acrolein on hypoxia/reoxygenation (H/R) injury in H9c2 cardiacmyocytes and investigate the intracellular signaling pathways. METHODS: Hypoxia/reoxygenation (H/R) injury model was established with H9c2 cells. The H9c2 cells were divided into four groups, the control group, acrolein group (ACR), H/R group, acrolein + H/R group (ACR + H/R). H9c2 cells pretreated with or without acrolein (10 micromol/L) for 30 min were exposed to 2 h hypoxia and 16 h reoxygenation. The effect of acrolein on the cellular viability and apoptosis of H9c2 cells was measured by MTT assay, DAPI stainning and flow cytometry (FCM) respectively. The expression of apotosis-related proteins (cytochrome c, caspase 9 and caspase 3) in the H9c2 cells was detected by Western blot. RESULTS: Compared with mere H/R treatment, the decrease in cell viability and increase in the number of apoptotic cells in H9c2 cells subjected to H/R were significantly exacerbated in the presence of acrolein (P < 0.05). The liberation of cytochrome c from mitochondria to cytosol, the cleavages of the initiator caspase 9 and the effector caspase 3 have been observed after pretreatment with acrolein followed by H/ R in H9c2 cells. CONCLUSION: Acrolein could aggravate H/R injury and that this effect may be related, in part, to the modification of proteins involved the release of cytochrome c from mitochondria to cytosol and activation of caspases cascade reaction.