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Objective To study whether or not CD40 gene is a target of miR-503 in U937 cells,and to observe the regulatory effects of miR-503 on expression of CD40 induced by irradiation in U937cells.Methods The miR-503 sequence was inserted into pcDNA-DEST-47 plasmid to construct the eukaryotic expression vector (pcDNA-DEST-miR-503) and to construct the CD40 gene 3′-UTR luciferase reporter plasmid (psiCHECK2-CD40) at the same time.They were used to transfect U937 cells together for analysis of the regulatory effects of miR-503 on the expression of CD40.Meanwhile the miR-203 and miR-29b were used as controls to observe whether or not CD40 gene was a target of miR-503.The expression change of CD40 after irradiation,and the inhibitory effect of miR-503 on the expression of CD40 was confirmed by Western blot assay.The expression of miR-503 was detected by real-time RT-PCR (qPCR) after irradiation with doses of 5.0 Gy.Results The expression of luciferase in the group of transfected with pcDNA-DEST-miR-503 and psiCHECK2-CD40 plasmids was significantly lower than that in the group transfected with empty plasmid and CD40 gene (t =3.16,P ＜ 0.05).And the miR-203 and miR-29b could not inhibit the activity of CD40 luciferase,but the miR-503 could significantly inhibit the activity of it (t =5.25,P ＜ 0.01 ).The expression of CD40 protein in U937 cells was decreased after the cells were transfected with pcDNA-DEST-miR-503.After irradiation with dose of 5.0 Gy,the expression of miR-503 were increased (t =3.63 - 17.00,P ＜0.01 ) and the expression of CD40 protein decreased.Conclusions The CD40 gene might be the target of miR-503,and miR-503 could regulate the expression of CD40 gene.Irradiation could up-regulate the expression of miR-503 and inhibit the expression of CD40 protein in U937 cells.miR-503 might play a role in the process of regulation of irradiation on expression of CD40 protein in tumor cells.

Objective To investigate the effects of TLR4 on the radiosensitivity of tumor cells.Methods The cell lines of RAW264.7,Lewis,MFC,Hepal-6,Bl6,and NIH3T3 were irradiated with 5 Gy X-rays or sham-irradiated.24 h after irradiation,the expression of TLR4 was detected by flow cytometry.According to the TKR4 level,cells were divided into three groups:without treatment,LPS stimulation and TAK242 block.CCK-8 kit and Annexin-V Apoptosis Kit were used to detect cell proliferation,apoptosis and cell cycle distribution of each group.Results After 24 h of 5 Gy ionizing radiation,TLR4 was significantly increased in Lewis cells (t =-8.68,P ＜0.01) but decreased in MFC cells (t =25.8,P ＜ 0.01) and had no significant changes in Hepal-6,B16 and RAW264.7 cells.In addition,the proliferation vitality (t =57.62,-6.23,P ＜ 0.01) and survival fraction (t =13.37,19.24,P ＜ 0.01) of the Lewis and MFC cells were reduced especially for the TLR4-blocked cells,and the apoptosis rates of both Lewis (t=-167.85,P＜0.01) and MFC cells (t=-26.45,P＜0.01) were elevated.The percentages of G0/G1 phase and S phase Lewis cells were significant increased (t =8.68,14.89,P ＜ 0.01) but its G2/M phase were reduced (t =-37.48,P ＜ 0.01).However,the percentages of G0/G1 phase and S phase MFC cells were obviously reduced (t =20.31,4.48,P ＜ 0.01) and G2/M phase increased (t =-13.06,P ＜ 0.01).For both cell lines of Lewis and MFC,the cycle distribution of TAK242 and LPS groups didn't change significantly.Conclusions High expression TLR4 in the Lewis cells is related to cell proliferation and apoptosis but not cell cycle distribution,and hence TLR4 could influence the radiosensitivity of tumor cells.

Objective To detect the expression of DNA damage response genes induced by radiation in human peripheral blood lymphocyte,and to explore the new biomarkers of radiation.Methods The human peripheral blood cells were irradiated to X-rays at different doses of 0,1,2,3,4,and 5 Gy.The quantitative real.time qPCR wag used to detect the expressions of cyclin-dependent kinase inhibitor l a gene(Cdknl a)and growth arrest and DNA damage inducible gene(Gadd45a)in lymphoeytes at 4 and 24 h post-irradiation,respectively.The method of CB mieronucleus was used to determine the change of micronucleus ratio.Results The expression of Cdknl a in peripheral blood lymphocytes wag increased significantly at 4 and 24 h post-irradiation to 0-5 Gy.reached the peak at 4 Gy and began to decrease at 5 Gy,which showed a dose-dependent manner(r=0.946,0.975,P<0.05).Similarly,the expression of Gadd45α in human peripheral blood lymphocytes was also increased significantly at 4 and 24 h post-irradiation to 0-5 Gy in a dose-dependent manner,while the expression of Gadd45a at 4 h wag higher than that at 24 h(r=0.936,0.797,P<0.05).The ratio of micronuclei wag increased significantly at 4 and 24 h post-irradiation to 0-5 Gy(r=0.990,0.984,P<0.05).Conciusions Cdknl a and Gadd45α expression could be increaged significandy at 4 and 24 h post-irradiation to 0-5 Gy,showing a good linear relationship.which might be candidate for radiation biological dosimeter.

Objective To observe the changes in expressions of spleen regulatory T cells (Tregs)and the related factor forkhead box protein-3 (Foxp3) after irradiation with different doses of X-ray in mice at different times,and to elaborate the effects of X-rays on regulatory T cells and Foxp3.Methods 112male ICR mice were randomly divided into 2 groups and irradiated by X-rays at the doses of 0.075 and 2 Gy,respectively.The mice were killed at 0,4,8,16,24,48,and 72 h post-irradiation and the spleens removed.Flow cytometry was used to detect the percentage of CD4 + CD25 + Treg and protein expression of (Foxp3),and RT-PCR was used to exmiamine the mRNA expression of Fox3.Results Compared with those before irradiation,the CD4 + CD25 + Treg positive rates began to increase and peaked at 8 h post-irradiation with 0.075 Gy at 8,16,24,72 h(t = 8.73,10.55,4.21,4.65 ,P ＜ 0.05) and 2 Gy at 8,16,48,72 h(t = 4.65,4.28,3.71,2.88,P ＜ 0.05),and then slightly decreased,but still remained at high levels.The mRNA protein levels of Fox3 did not change significantly after exposure to the dose of 0.075 Gy,but began to significantly increase at 8 h after exposure to the dose of 2 Gy.However,the Foxp3 protein level began to increase 4 h post-irradiation,peaked at 16 h,and then slightly decreased,but still ramained at high levels (t =2.59,3.37,3.70,3.20,P＜0.05).Conclusions The changes in expressions of Tregs and Foxp3 after high- and low-dose X-ray irradiation may be used to explain the differences in immune effects induced by ionizing radiation at different doses.

Objective To explore the role of PLC/PIP2 signal pathway in the changes of mouse thymus CD4 + CD25 + NRP1 + Treg and TGF-β1 after different doses of X-ray irradiation Methods 36 ICR mice were randomly divided into 6 groups according to the irradiation doses of 0,0.5,1.0,2.0,4.0 and 6.0 Gy,respectively.Flow cytometry was used to detect the expression of NRP1 + Treg,and ELISA was used to detect the expression of TGF-β1 in mouse thymocytes at 16 h post-irradiation.The EL-4 cells were irradiated by X-rays at the dose of 4.0 Gy after co-cultured with the PMA and TMB-8 for 2 hours.Flow cytometry was used to detect the expression of NRP1 + Treg,and ELISA was used to detect the changes of TGF-β1 at 48 h post-irradiation.Results The NRP1 + Treg appeared a transient decrease at both 0.5 and 1.0 Gy irradiation and reached its valley value at 1.0 Gy (t =6.96,P ＜ 0.01),then showed a dosedependent increase and reached its peak at 6.0 Gy (t =6.70,P ＜ 0.01).The TGF-β1 level decreased after 0.5 Gy X-rays (t =12.53,P ＜0.01),then increased at a dose-dependent manner and reached its peak at 4.0 Gy (t =10.40-19.56,P ＜ 0.01).Compared with the sham-irradiation,NRP1 + Treg was decreased significantly after PMA treatment (t =3.06,P ＜ 0.01),while it was up-regulated significantly after irradiation in the presence of PMA (t =8.27,P ＜ 0.01).TGF-β1 was reduced in the presence of PMA with or without irradiation (t =10.46-39.69,P ＜ 0.01).NRP1 + Treg and TGF-β1 were increased significantly after TMB-8 treatment (t =5.53-44.26,P ＜ 0.01).Conclusions NRP1 + Treg cells and TGF-β1 were up-regulated after a high dose radiation,and the PLC/PIP2 signal pathway may participate in the regulation.

Objective To analyze the effect of high and low dose radiation on the expressions of Th1,Th2 and Th3 /Tr1 related-genes in mice thymocytes and investigate the possible underlying molecular mechanism.Methods ICR mice were randomly divided into low-dose group (0.075 Gy),high-dose group (2.0 Gy) and sham-control group.The mouse thymus tissue was extracted at 16 hours after irradiation and the expressions of Th1-Th2-Th3 related genes were measured by PCR array.Results Eight genes were up-regulated and five genes were down-regulated after low dose radiation (0.075 Gy);while 54 genes were up-regulated and three genes were down-regulated after high dose (2.0 Gy) radiation.These genes included Th1 cell related genes,Th2 cell related genes,Th3/Tr1 cell related genes,Th1/Th2 immune response genes and transcription factor related genes.Low dose radiation induced up-regulation of Stat4 and Socs1 of genes related to the Th1 cells,and it induced down-regulation of IL-4ra,Cebpb,Gata3 and Tgfb3 associated with Th2 and Th3 cells,which lead to Sftpd genes up-regulation of Th1 immune response eventually.The high dose radiation up-regulated all of Th1,Th2 and Th3/Tr related genes and also enhanced the expressions of Cd86,IL-18,IL-10 and Irf4 genes related to Th2 immune response,but it did not alter the gene expression of Th1 immune response.Conclusions Low-dose radiation induces Th1-type immune response,while high doses radiation triggers Th2 type immune response.

Objective To explore the effect of miR-9 on the expression of NRP1 and its radiation effects in A549 cells.Methods Bioinformatics was used to analyze the potential binding sites of has-miR-9 and NRP1-3'UTR.The miR-9 sequence was inserted into pcDNA-DEST-47 plasmid to construct the eukaryotic expression vector (pcDNA-DEST-miR-9) and to construct the NRP1 gene 3'UTR luciferase reporter plasmid (pEZX-MT05) at the same time.They were simultaneously transferred into A549 cells for analysis of the regulatory effect of miR-9 on the expression of NRP1.Meanwhile miR-29b was used as a negative control to observe whether or not NRP1 gene was a target of miR-9.After 10 Gy irradiation,the expression of NRP1,and the inhibitory effect of miR-9 on it was confirmed by Western blot assay.The expression of miR-9 was detected by real-time PCR.Results It was found that miR-9 reduced the luciferase activity of NRP1-3'UTR wild plasmid (t =3.906,P ＜ 0.05) but not NRP1-3' UTR mutant plasmid.This luciferase activity was not inhibited by other types of miRNA (miR-29b).The expression of NRP1 protein in A549 cells was decreased after the cells were transfected with miR-9 mimic.After irradiation with dose of 10 Gy,the expression of miR-9 were decreased (t =37.319,P ＜ 0.05) and the expression of NRP1 protein were increased.Conclusions miR-9 regulates the expression of NRP1 by targeting 3'UTR site of NRP1 gene in A549 cells.

This paper summarizes and discusses the research and achievements in the effect of irradiation on extending the shelf life and quality guarantee period of seafood, on the quality of seafood, and on seafood sterilization, and seafood irradiation biological dosimeter study, and defines the concepts related to seafood irradiation. Moreover, we propose that irradiation sterilization on severe acute respiratory syndrome coronavirus 2 of cold-chain seafood and seafood irradiation dose control are the main research content and directions.

Health monitoring of radiation workers is an important part of the radiation protection system. Occupational health examination is very important for the safe use of nuclear energy technology. This article analyzes the detection results of radiation-sensitive indicators reported in the literature to investigate the health status of radiation workers and to provide a reference for the further study of sensitive indicators in health monitoring of radiation workers.