Gene transcriptional profiles in human lymphoblastoid cells with low and high doses of irradiation / 中华放射医学与防护杂志

Objective To compare the gene expression difference between 0.1 and 5 Gy X-ray irradiated cells,and to explore its possible mechanism.Methods A cDNA microarray corresponding to 45033 human genes was used to analyze the transcriptional profiles of normal human lymphoblastoid AHH-1 cells at 4 h after 0.1 or 5 Gy irradiation.The genes with a fold change ≥ 2.0 were identified as the differentially expressed genes.real-lime PCR and Western blot were used to confirm the expression of PERP.Results The microarray assay showed that there were 760 up-regulated genes and 1222 down-regulated genes in the cells at 0.1 Gy,while there were 744 genes down-regulated and 457 genes up-regulated in the cells at 5 Gy.In addition,55 genes were commonly up-regulated and 339 genes commonly down-regulated at 0.1 and 5 Gy.The predominant biological processes of the differential genes responding to low-dose radiation include cell-cell signaling transduction and DNA damage response,and the altered genes after 5 Gy irradiation were related to cell proliferation,differentiation,and apoptosis.Moreover,the expression of PERP gene was down regulated,which was consistent with the data of microarrey assay.Conclusions The quantitative and qualitative differences in the gene expressions may contribute to the diversed biological effects induced by low or high doses of ionizina radiation.

Study on radiosensitivity by targeting HIF-1α in human lung cancer and growth of the transplanted tumors / 中华放射医学与防护杂志

Objective To observe the radiosensitivity by targeting HIF-lα in human lung cancer and the effects on tumor growth in nude mice.Methods Radiosensitivity of A549 and A549/HIF-1α ( － ) cells were tested by clonogenic forming assay.A549/HIF-1 α( － ) cells and A549 cells were injected into the male BALB/C nude mice.Tumor growth was observed.The expression of HIF-1α and microvessel density were detected by immunohistochemistry method.Results SERs of HIF-1α gene silencing were 1.03 in normoxia and 1.65 in hypoxia.The sizes of tumor xenografts derived from A549/HIF-1α( － ) cells were significantly reduced compared to those of the xenografts derived from A549 cells.HIF-1 α protein staining result showed a dramatic decrease in tumors from A549/HIF-1α ( － ) mice.The microvessel densities (MVD) were 19.83 ± 4.09 in A549 group and 11.61 ±3.04 in A549/HIF-lα (-)group(F=15.57,P ＜0.05 ).Conclusions Hypoxia-induced radio-resistance in lung cancer A549 cells could be reversed by silencing the HIF-1α.It also retards the growth of tumor xenografts,decreases HIF-1α expression and reduces the vascularity.

Consistency of T-cell receptor gene mutation between lymphocytes in rats after irradiation in vivo and in vitro / 中华放射医学与防护杂志

Objective To observe the consistency of T-cell receptor (TCR) genes mutation in lymphocytes in rats after irradiation in vivo and in vitro.Methods A total of 48 female rats were randomly divided into 6 equal groups.Peripheral blood samples from them were collected to separate the lymphocytes and then irradiated to X-ray irradiation with the dose rate of 200 cGy/min at the doses of 0,0.5,0.75,1.0,2.0,and 3.0 Gy,respectively.Then all the lymphocyte samples were cultured for 7 days.Flow cytometry with direct immunofluorescence was used to detect the TCR gene mutation.The levels of TCR gene mutant frequency (TCRMF) of different groups were calculated.Results The TCRMF levels of different groups after irradiation in vivo and in vitro all displayed a dose-dependent manner and there were no significant differences in the TCRMF between different dose irradiation groups(t = -1.1-0.3 ,P ＞0.05).Conclusions A consistency of TCRMF after irradiation in vivo and in vitro is proven.The results of TCRMF of peripheral blood lymphocytes irradiated in vitro by flow cytometry can precisely reflect the TCR genes mutation after whole-body irradiation.

X-ray induced TCR gene mutation of peripheral blood lymphocytes / 中华放射医学与防护杂志

objective To study the TCR gene mutation in peripheral blood lymphocytes induced by X-ray exposure using cultured lymphocytes cloning method.Methods Freshly isolated peripheral lymphocytes from healthy aduh donors were irradiated with X-ray in doses ranging from 0 to 8 Gy and cultured with interleukin2 and phytohemagglutinin for 7 days.The mutant frequencies of TCR gene(TCR MF)were detected by flow cytonletry and the dose response curves were fitted.Results TCR MF increased with the dose going up.An aquadratic polynomial dose response model was fitted.Conclusions TCR gene mutation could which serve as a potential biological dosimeter.It might be applied for the estimation of biological dose in emergency exposure.

Cytogenetic investigation on underground workers in gold mine / 中华放射医学与防护杂志

Objective To investigate the chromosome damage in peripheral lymphocytes of underground gold miners.Methods Conventional method and cytokinesis-block micronuclens assay were used to analyze frequency of chromosome aberrations and micronucleus in peripheral lymphocytes in 58 gold miners,respectively.Results Frequencies of chromosome-type aberrations,ehromatid-type aberrations and total aberrations were higher in the miners than those in the control group(0.72%,0.41%,1.16% vs 0.14%,0.18%,0.33,X2=44.322,9.501,50.476,P＜0.01).Both micronucleated cell rate and micronucleus rate were higher in the miners group than those in the control group(10.8‰ and 11.6‰ vs 8.7‰ and 9.0‰,X2=8.672,12.546,P＜0.01).Frequencies of chromosomal aberrations and micronucleus proportionally increased with underground working years.Compared with those miners who had worked underground 6 years or shorter,both frequencies were statistically higher among the miners who had worked underground for more than 21 years(P＜0.05).No difference was found among other groups of working years(P＞0.05).Compared with the control group,both frequencies increased in the miner group,and the differences were statistically significant(X2=2.395,P＜0.05 for chromosomal aberrations and X2=2.319,P＜0.05,respecfvely).The common types of chromosome aberrations were acentrie fragments,while chromatid break and dicenrics were subordinate.Conclusions Chromosomal damages were observed in the gold workers who exposed high radon in the underground mining.