Amyloid-beta protein 25-35 induced apoptosis in rabbit aortic smooth muscle cells:an experimental study

Objective To investigate the effect of amyloid-beta protein 25-35(Aβ25-35)induced apoptosis in cultured vascular smooth muscle cells(VSMCs)in vitro.Methods The normal VSMCs of rabbit thoracic aorta were selected,and they were divided into experimental and control groups.The experimental group was incubated with Aβ25-35 and VSMCs,and they were redivided into 10,20,50,and 100 μmol/L groups according to their Aβ25-35 concentrations;the control group was incubated with isotonic saline solution and VSMCs.Each group was incubated for 1,3,and 10 d,respectively.Apoptosis was detected with annexin V-fluorescein isothiocyanate(V-FITC)and propidium iodide(PI)staining methods.Apoptosis was observed quantitatively with flow cytometer.Results The apoptosis rates of VSMCs were 5.3±1.4% and 25.9±5.8% incubated for 3 d in the 10 and 20 μmol/L Aβ25-35 groups.The apoptosis rate was 94.0±14.4% incubated for 10 d in the 100 μmol/L Aβ25-35 group,and these differences were significant(P0.05).The apoptosis rates increased with the Aβ25-35 concentrations and incubation time.The early apoptotic cells presented green fluorescent label which could be observed in the 20 μmol/L Aβ25-35 group incubated for only 1 d;both green and red fluorescent labels could be observed in the 100 μmol/L Aβ25-35 group incubated for 10 d,and they were in the late apoptotic stage or the dying cells.Conclusion Aβ25-35 may exert cytotoxic effects on VSMC through apoptotic pathway.