Protective effects and mechanism of Panax Notoginseng saponins on oxidative stress-induced damage and apoptosis of rabbit bone marrow stromal cells

To investigate the effects and possible mechanism of Panax Notoginseng saponins (PNS) on oxidative stress-induced damage and apoptosis in bone marrow stromal cells (BMSCs). BMSCs were isolated and cultured from 2-month-old New Zealand rabbits by the density gradient centrifugation combined with adherent method. The third passage cells were used for subsequent experiments. Oxidative stress was induced in cultured BMSCs by H2O2 (0.1 mmol/L). BMSCs were pretreated with 25-200 mu g/mL PNS for 4 h before H2O2 treatment. Proliferation of BMSCs was observed using MTT assay. Alkaline phosphatase (ALP) activity, as an index of early osteoblastic differentiation, was determined with an ALP assay kit. Flow cytometry was used to observe the apoptosis of BMSCs by staining with annexinV-FITC/propidium iodide. Oxidative stress level was examined by reactive oxygen species (ROS) assay. The protein expressions of Bax, Bcl-2 and Caspase-3 in BMSCs were analyzed by Western blotting. PNS had different concentration-dependent effects on proliferation and osteoblast differentiation of BMSCs induced by H2O2. A PNS concentration of 100 mu g/mL was determined as the optimal effective concentration. PNS markedly attenuated H2O2-induced apoptosis rate from 41.91% to 14.67% (P < 0.01). PNS significantly decreased ROS level induced by H2O2 (P < 0.01). Furthermore, pretreatment with PNS significantly reversed H2O2-induced inhibition of Bcl-2 expression and augmentation of Bax and Caspase-3 expression (P < 0.01). PNS had a protective effect on oxidative stress-induced damage and apoptosis in cultured rabbit BMSCs through scavenging ROS and regulating the Bcl-2/Bax pathway.