The Effect Of Selenium On Homocysteine-induced Apoptosis In Vascular Endothelial Cells

Objective:Vascular endothelial cells have endocrine function and play an important role inthe formation and development of cardiovascular disease. Endothelial cells apoptosisis one of the pathological changes during the cardiovascular disease.Homocysteine-induced endothelial cells apoptosis is the independent risk factor ofcardiovascular disease. In this project, we studied the mechanism of homocysteine-induced apoptosis, and examined the effect of selenium on homocysteine-inducedapoptosis in vascular endothelial cells.Methods:①Cells were divided into control group, homocysteine (Hcy) group, Cu groupand Se group. The effect of Hcy, Cu and Se on cells viability were detected throughCCK-8. In the Hcy group, cells were treated with Hcy at different concentrations(0,100μM,250μM,500μM,1000μM) for24h in vitro．In the Cu group，cells weretreated with Cu at different concentrations(0,5μM,10μM,15μM,20μM) for48hin vitro. In the Se group，cells were treated with Se at different concentrations(0,100nM,300nM,500nM,1000nM) for48h in vitro. All the treatments were carriedout after cells inoculation for24h.②Cells were divided into control group and Cu+Hcy group. After inoculation,cells were treated with Cu at the concentration of15μM. Then, cells were treatedwith Hcy at different concentrations (0,100μM,250μM,500μM,1000μM) in thepresence of Cu for24h. Cells viability was detected through CCK-8.③Cells were divided into control group, Cu+Hcy group and Cu+Hcy+Se group.The concentrations of Hcy, Cu and Se were500μM,15μM and100nM respectively.In Cu+Hcy group and Cu+Hcy+Se group, cells were pretreated with Cu and Se for12h. After pretreatment, cells were treated with drugs for24h. Cells viability,apoptosis, ROS level, mitochondrial membrane potential, activity of the caspase3andcaspase9, activity of GPx, Bax and Bcl-2transcription were detected in turn. Results:⑴Cells viabilityHcy at the concentration of100μM could not reduce cells viability, comparedwith the control（P>0.05）. Others could reduce cells viability (P<0.05). Comparedwith the control, Cu had no effect on cells viability（P>0.05）.Se could not reducecells viability at the concentration of100nM, compared with the control（P>0.05）.Cells viability significantly decreased, when the concentration of Se was300nM,500nM or1000nM (P<0.05). Hcy could significantly reduce cells viability in the presentof Cu, compared with the control (P<0.05). Se could attenuate the decrease of cellsviability induced by the Hcy in the present of Cu.⑵ApoptosisApoptosis of vascular endothelial cells significantly increased in Cu+Hcy groupand Cu+Hcy+Se group, compared with the control (P<0.05). Higher percentage ofapoptosis was observed in Cu+Hcy+Se group compared with the Cu+Hcy group(P<0.05). Se could attenuate the apoptosis of vascular endothelial cells.⑶ROS levelROS level increased in Cu+Hcy group and Cu+Hcy+Se group, compared withthe control (P<0.05). ROS level of Cu+Hcy group was higher than Cu+Hcy+Se group(P<0.05). Se could attenuate the increase of ROS level.⑷Mitochondrial membrane potentialMitochondrial membrane potential of Cu+Hcy group declined compared withthe control. Se could attenuate the decline of mitochondrial membrane potential.⑸Activity of GPxActivity of GPx was lower in Cu+Hcy group and Cu+Hcy+Se group, comparedwith the control (P<0.05). The activity of GPx was higher in Cu+Hcy+Se group,compared with the Cu+Hcy group (P<0.05). Se improved the activity of GPx.⑹Activity of caspase3and caspase9Activity of caspase3and caspase9increased in Cu+Hcy group and Cu+Hcy+Segroup, compared with the control (P<0.05). Both the Activity of caspase3andcaspase9were lowered in Cu+Hcy+Se group, compared with the Cu+Hcy group(P<0.05). Se could lower the activity of caspase3and caspase9. ⑺Expression of Bax and Bcl-2①Expression of Bax increased significantly in Cu+Hcy group and Cu+Hcy+Segroup, compared with the control (P<0.05). Expression of Bax decreased inCu+Hcy+Se group, compared with the Cu+Hcy group (P<0.05). Se could make theexpression of Bax decline.②Expression of Bcl-2decreased significantly in Cu+Hcy group andCu+Hcy+Se group, compared with the control (P<0.05). Expression of Bcl-2inCu+Hcy+Se group was more than Cu+Hcy group (P<0.05). Se could make theexpression of Bcl-2increase..Conclusion:⑴Hcy without Cu has no effect on viability of vascular endothelial cells at theconcentration of100μM, and has slightly effect on vascular endothelial cells at theconcentration of250μM to1000μM.⑵H cy can reduce viability of vascular endothelial cells significantly at theconcentration of100μM to1000μM when the concentration of Cu is15μM.⑶Secan attenuate the apoptosis induced by Hcy and lower the ROS level in thepresence of Cu, which could be related to the activity of GPx, caspase9, caspase3andexpression of Bax, Bcl-2.