Paeoniflorin isolated from Paeonia lactiflora attenuates osteoblast cytotoxicity induced by antimycin A.

The protective effects of paeoniflorin isolated from Paeonia lactiflora against pharmacological inhibition of the respiratory chain were studied using osteoblastic MC3T3-E1 cells. Here we show that paeoniflorin decreases cell death induced by antimycin A, an inhibitor of mitochondrial complex III. Paeoniflorin restored antimycin A-induced inactivation of phosphoinositide 3-kinase (PI3K) and thioredoxin reductase, suggesting that PI3K and thioredoxin reductase may be involved in paeoniflorin-induced cytoprotective responses. We also examined the effect of paeoniflorin on mitochondrial dysfunction and oxidative stress induced by antimycin A. Paeoniflorin inhibited mitochondrial membrane potential dissipation, ATP loss, inactivation of complexes I and IV, cytochrome c release, and cardiolipin oxidation induced by antimycin A. In addition, paeoniflorin prevented antimycin A-induced ROS release and nitrotyrosine increase. These results imply that paeoniflorin protects osteoblasts from antimycin A-induced cell death via improved mitochondrial function.