Protective Effects Of Procyanidins On VSMCs Oxidative Stress And Apoptosis Induced By PM2.5 And Its Mechanism

Objective: In our study,we used rat vascular smooth muscle cells(VSMCs)as evaluation models for toxicity studies.The purposes of this study was to observe the protective effect of procyanidins on PM2.5-induced apoptosis of VSMCs and to explore potential mechanism.Method: The primary vascular smooth muscle cells were isolated from thoracic and abdominal aorta of Male SD rats.The experiment was divided into control group,PM2.5 group(final concentration 100 ?g/mL)and different concentrations of PC group(final concentration of 5?mol/L,10 ?mol/L,20 ?mol/L).The cell viability was detected by iCELLigence RTCA real-time label-free cell function analyzer.VSMCs were stained with DCFH-DA and the levels of Reactive oxidative species(ROS)in the cells were observed by fluorescence microscope.Apoptosis rate was detected by flow cytometry using Annexin-V/PI double staining.Cells were treated with Hoechst 33258 and morphological changes of apoptotic cells were observed by fluorescence microscopy.The activity of SOD and MDA in cells were determined by kit.Western Blot was used to detect the expression levels of Bax,Caspase-3,Bcl-2,Nrf2,HO-1 and NQO1.Statistical analysis was performed using the SPSS 21.0 statistical package.Data were expressed as ?x ± SD.The t test was used for comparison between the two groups.P<0.05 was considered statistically significant.Results:1.Compared with the control group,the viability of VSMCs was significantly decreased in the PM2.5 group;the cell viability was increased in the procyanidins group compared with the PM2.5 group.2.Compared with the control group,the activity of SOD was significantly decreased,while the production of ROS and MDA was significantly increased in the PM2.5 group(P<0.05).Compared with the PM2.5 group,the activity of SOD was increased in the high-dose procyanidins intervention group,while the production of ROS and MDA was decresed in the procyanidins group(P<0.05).3.There were few apoptotic cells and most of the nuclei showed a round or elliptical shape with almost no apoptotic bodies in the control group;The apoptosis rate of VSMCs was significantly increased,the shape of the nuclei was irregular,and chromatin condensation and apoptotic bodies appeared in the PM2.5 group;Compared with PM2.5 group,the apoptosis rate of was decreased,and the occurrence of nuclear fragmentation and apoptotic bodies was also reduced in the procyanidins group.4.Compared with the control group,the expression levels of Caspase-3 and Bax were significantly increased,while the expression levels of Bcl-2,Nrf2,HO-1 and NQO1 were decreased in PM2.5 group(P<0.05);Compared with PM2.5 group,the expression levels of Caspase-3 and Bax were decreased,while the expression levels of Bcl-2,Nrf2,HO-1 and NQO1 were increased in the procyanidins group(P<0.05).Conclusion: Procyanidins protects VSMCs from PM2.5-induced the oxidative stress and apoptosis through the activation of Nrf2/HO-1 pathway.