The Research On The Detection Of GADD45 Gene Expression As A Biomarker For Radiation Biodosimetry

In nuclear warfare and accident,differentiating and aiding a great deal of victims being irradiated is the key to salvaging the victims who could be cured.And successful salvation need for estimating the dose fast and accurately.At present,there are several ways to estimate the dose,including the physical and biological methods,and biological methods has its advantages.Radiation Biodosimeters plays a vitally important role in assessing the doses of radiation victims and in the research on cell response to radiation.Many researches have been conducted during the past half-century,and hundreds of targets have been assessed.Ideal radiation biodosimeter possesses the following features:inducible after ionizing radiation(IR);proportionate to exposure dose;method simple and convenient.However,no radiation biodosimeter at present can meet all the these requirements.Ionizing radiation could elieit several types of cell response.GEC(Gene Expression Change)of Gadd45 after IR has been paid great attention.Research in vitro by Armed Forees Radiobiology Research Institute showed that Gadd45 mRNA increases promptly after IR and its mRNA level is proportionate to exposure dose.To point out,increasing promptly after IR and easily test,the most obvious features of Gadd45,are defective in present chromosome aberration analysis which is the most popular method.Whereas assessing the doses promptly after IR is vital to the diagnosis and treatment of radiation victims.Therefore,it has become a focus if Gadd45 could function as a practical radiation biodosimiters of GEC type.We set up the relative real-time quantitative PCR by method of comparing C_T(Threshold cycle,C_T),SYBR Green real-time PCR technology was used to assay GADD45 gene expression at mRNA level exposed to different dose,meanwhile choosing housekeeping gene GAPDH,was applied to rectify the quantity of every dose.The up-regulation of gene GADD45 was dose-dependent in transcription level after irradiation,reaches the peak at 4Gy irradiaton,and still stayed in relatively high level at 8Gy.A linear regression equation is established,(?)=3.408+1.528x,R~2=0.787.After exposured to 2Gy X-ray,mRNA expression showed up-regulated at 1h,reached the peak at 4h,and still not get back to beginning level.GEC of GADD45 analysis using SYBR Green real-time PCR is rapid,sensitive and reproducible.