The protective effect of picroside II against hypoxia/reoxygenation injury in neonatal rat cardiomyocytes.

BACKGROUND

Picroside II, an iridoid glucoside found in the root of Picrorhiza scrophulariiflora Pennell (Scrophulariaceae), has been demonstrated to possess potent antioxidant activity. However, whether picroside II has a protective effect against hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury is poorly understood.

OBJECTIVE

To explore the cardioprotective role of picroside II against oxidative stress induced by H/R injury in neonatal rat cardiacmyocytes.

METHODS

The viability and cellular damage of cardiomyocytes were assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolim bromide (MTT) and lactate dehydrogenase (LDH) assays, respectively. The activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), the levels of reduced (GSH) and oxidized glutathione (GSSG), and the contents of malondialdehyde (MDA) were determined by a colorimetric method. The levels of intracellular reactive oxygen species (ROS) and calcium were evaluated by flow cytometric analysis.

RESULTS

We analyzed the effective half-maximal concentration for protection from the dose-response curves and obtained the concentration of 50 µg/mL as EC(50). Pretreated cardiomyocytes with picroside II (50-200 µg/mL), prior to H/R exposure, inhibited LDH activity in culture media and increased cell viability in a dose-dependent manner. This protective effect was accompanied by significantly increasing reduced GSH contents and the activities of SOD and GSH-Px and attenuating MDA and GSSG contents in response to H/R injury. Furthermore, treatment with picroside II also inhibited ROS production and calcium accumulation in cardiomyocytes.

CONCLUSIONS

The present study demonstrates that picroside II protects cardiomyocytes against oxidative-stress injury induced by H/R through reduction of ROS production and calcium accumulation and enhancement of the activity of antioxidant defense.