Effects Of Silencing SSB1 Gene On Post-irradiation Proliferation And Repair Of Rat Submandibular Gland Cells

Objective To investigate the effects of silencing single-stranded DNA-binding protein1(SSB1)on proliferation and repair of rat submandibular gland(SMG)cells after irradiation,and explore the relationship between SSB1 and radioactive damage repair of DNA.MethAs The primary rat SMG cells were obtained by mechanical-enzyme digestion and identified by immunohistochemical.The cells were divided into three groups including blank control,negative control and shRNA transfection group.The shRNA was transfected into cells by recombinant adenovirus vector.Realtime quantitative PCR(qRT-PCR)and Western Blot were used to detect the expression of SSB1 after silencing.The cell viability was detected by CCK-8assay.Immunofluorescence was performed to observe the dynamic formation ofγH2AX foci.Results The SMG cells were positively stained for both Pan CK andα-Amylase.The efficiency was about 90% at 72 h post-transfection,andcompared with the control group,the expression of SSB1 was significantly decreased in cells after transfection with shRNA(P<0.05).Before irradiation with 5Gy of γ rays,the cell viability of shRNA transfection group decreased indistinctively until 120 h that the A value was lower than the blank control group significantly(t =3.29,P <0.05).After radiation,the cell viability of shRNA transfection group was lower than the control groups significantly(F=10.19~30.13,P<0.05).Immunofluorescence showed that 1 h after radiation,γH2AX foci of the shRNA transfection group and the blank control group all reached maximum(t?=1.14,P >0.05)。Afterwards,the γH2AX foci of shRNA transfection group decreased more slowly than the blank control group.Conclusions After silencing of the expression of SSB1,the SMG cell could be more radiosensitive.For the SMG cell,SSB1 may play an important role in repair of DSBs induced by radiation.