Panax notogiseng saponin inhibits ischemia-induced apoptosis by activating PI3K/Akt signal pathway in cardiomyocytes

The panax notoginseng saponin(PNS) had been clinically used for the treatment of cardiovascular diseases and stroke in China.It had been demonstrated that PNS could protect cardiomyocytes from injury induced by ischemi- a,but the underlying molecular mechanisms of this protective effect were still unclear.This study was aimed to investigate the protective effect and molecular mechanisms of PNS on apoptosis in H9c2 cells in vitro and rat myocardial ischemia injury model in vivo.Annexin-V/PI assay shew that PNS could protect H9c2 cells from apoptosis induced by serum, glucose and oxygen deprivation(SGOD) in a dose-dependent manner.However,the anti-apoptotic effect of PNS was reversed by LY294002,a specific PI3K inhibitor.This antiapoptotic effect of PNS was confirmed by JC-1,a specific probe of mitochondrial membrane potential staining.PNS could significantly increase phos-Akt in H9c2 cells by Western blot assays and its effect could be inhibited by LY294002.Furthermore,PNS could improve ischemic-induced left ventricular function as reflected by EF,LVDd and LVDs.PNS could also inhibited cellular apoptosis in myocardial tissues in ischemic rats by TUNEL assay.PNS administration also increased the expression of phos-Akt in rat ischemic myocardial tissues.These results suggested that PNS could protect myocardial cells from apoptosis induced by ischemia in vitro model and in vivo model through activating-PI3K/Akt signal pathway which may be meaningful for further understanding the molecular mechanisms of cardiac protection of PNS.And the results might be useful in treatment of myocardial ischemia in future.

Protective Effects and Mechanism of Panax Notoginseng Saponins on Oxidative Stress-Induced Damage and Apoptosis of Rabbit Bone Marrow Stromal Cells

Objective： 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）.Methods： 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 μg/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.Results： PNS had different concentrationdependent effects on proliferation and osteoblast differentiation of BMSCs induced by H2O2.A PNS concentration of 100 μg/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）.Conclusion： 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.