Effects of fractionated low-dose ionizing radiation in the induction of EA.hy926 cell senescence
Objective To investigate the mechanism of fractionated low-dose ionizing radiation(LDIR)in the induction of EA.hy926 cell senescence.Methods EA.hy926 cells were irradiated with X-ray at 0,50,100,and 200 mGy× 4,re-spectively,and cultured for 24,48,and 72 h.Several indicators were measured,including the levels of cellular senescence-associated β-galactosidase(SA-β-gal)staining,mRNA levels of senescence-associated cell cycle protein-dependent kinase inhibitor genes CDKN1A and CDKN2A,reactive oxygen species(ROS),total antioxidant capacity(T-AOC),and phos-phorylated H2A histone family member X(y-H2AX).Results After 4 fractionated LDIR,compared with the control group,the treatment groups showed increased nucleus area,blurred cell edge,and increased SA-β-gal positive area(P＜0.05)at 24,48 and 72 h.After 4 fractionated LDIR,the mRNA level of CDKN1A increased in the 100 and 200 mGy × 4 groups at 24 and 48 h(P＜0.05),and CDKN2A mRNA level increased in the 100 and 200 mGy × 4 groups at 48 and 72 h(P＜0.05).The fluorescence intensity of ROS increased in treatment groups at 24,48,and 72 h after 4 fractionated LDIR(P＜0.05).After 4 fractionated LDIR,the T-AOC level increased in the 100 and 200 mGy × 4 groups at 24 h(P＜0.05),and T-AOC level increased in all treatment groups at 48 and 72 h(P＜0.05).After 4 fractionated LDIR,γ-H2AX fluorescence intensity increased in all treatment groups at 24 h(P＜0.05),and the fluorescence intensity increased in the 100 and 200 mGy × 4 groups at 48 and 72 h(P＜0.05).Conclusion Fractionated LDIR can induce cellular senescence in EA.hy-926 cells by impacting the cellular oxidation-antioxidation and oxidative damage levels,and the effects were relatively evid-ent at 100 and 200 mGy.
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