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Objective:To analyze the damage in hippocampal tissues of mice after whole-body irradiation with high- or low-dose ionizing radiation and to investigate the roles of microglia/macrophages polarization in the injury.Methods:C57BL/6 mice were randomly divided into three groups: sham irradiation group, low-dose group (0.05 Gy) and high-dose group (7 Gy). Low- and high-dose groups were respectively treated by whole-body irradiation with single dose of 60Co γ-rays. Hippocampal tissues of the mice were collected at 6 h, 1 d, 3 d and 7 d after irradiation. The morphology, structure and apoptosis of neurons were detected by HE staining, Nissl staining and Tunnel staining, respectively. RT-PCR and immunofluorescence assay were performed to detect the expression of M1 and M2 microglial markers at mRNA and protein levels in hippocampus tissues. The cognitive and emotional behaviors of mice were evaluated one month after the irradiation by Morris water maze, open field test, elevated plus maze and tail suspension test. Results:There were morphological and structural changes in the nerve cells in the hippocampus region of mice after irradiation, accompanied by apoptosis. Acute injuries occurred at 6 h after radiation, alleviated at 1 d and 3 d, and persisted at 7 d in a dose-dependent manner. The results of immunofluorescence staining and confocal imaging analysis showed that compared with the sham irradiation group, the high-dose group showed increased number of microglia, down-regulated expression of M1 microglial markers and up-regulated expression of M2 microglial markers in the hippocampus at 6 h and 1 d after radiation, while M2 microglial markers decreased at 3 d and 7 d after irradiation. PCR results showed that the expression of M1 and M2 microglial markers at mRNA level in the irradiation groups increased at 6 h after irradiation, but there was no statistical significance. The expression of related proinflammatory/anti-inflammatory factors was significantly up-regulated. The results of behavioral experiments showed that compared with the sham irradiation group, there was no statistical difference in cognitive or emotional behaviors at one month after irradiation.Conclusions:60Co γ-rays could damage mouse hippocampal tissues and result in the overexpression and different polarization patterns of microglia/macrophages in mice.
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Objective:To investigate the effect of ionizing radiation on the N 6-methyladenine (m 6A) modification profile of circular RNA (circRNA) in mouse bone marrow cells and provide scientific basis for revealing the relationship between RNA epigenetic modification and hematopoietic radiation injury. Methods:A total of twenty four C57BL/6 J mice were randomly divided into two groups: the healthy control group ( n=12), and ionizing radiation group ( n=12) irradiated in total body with 4 Gy of 137Cs γ-rays. At 5 min after irradiation, mice were killed and bone marrow cells were collected from the femur. Total RNAs were extracted and the changes in circRNA m6A modification profiles were investigated by RNA immunoprecipitation-high-throughput sequencing (MeRIP-Seq) technology and bioinformatics analysis. The representative alterations of m 6A peaks were validated by MeRIP-PCR assay. Results:325 and 455 m 6A sites were identified on circRNAs in the healthy control group and ionizing radiation group (178 common sites, 147 specific sites in the healthy control group and 277 specific sites in ionizing radiation group), respectively. 1 275 and 1 017 deriving genes of m 6A-circRNAs were identified in the healthy control group and ionizing radiation group (767 common genes, 508 specific genes in the healthy control group and 250 specific genes in ionizing radiation group), respectively. Compared with the control healthy group, 414 (178) m 6A peaks was significantly up- (down-) regulated in the ionizing radiation group( P < 10 -10; fold-change cut-off > 5). Moreover, Gene Ontology (GO) assay revealed that the deriving genes of circRNAs with differentially methylated m 6A sites between two groups involves various functions including chromatin regulation, ciliary transition fiber and poly (A)-specific ribonuclease activity. Kyoto Encyclopedia of Genes and Genomes (KEGG) assay revealed that the deriving genes of circRNAs with differentially methylated m 6A sites between two groups included numerous pathways such as platelet activation, Fc γ R-mediated phagocytosis and B cell receptor signaling pathway. Conclusions:Ionizing radiation triggers rapid alterations in the m 6A modification profile of circRNA in mouse bone marrow cells. The deriving genes of differentially methylated circRNAs are associated with a variety of functions and signaling pathways of hematopoietic radiobiology.
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OBJECTIVE: To identify the differentially expressed long non-coding RNAs (IncRNAs) in γ-rays irradiated p53 knockout HBE (HBEp53-/-) cells, and to provide more baseline information for further investigation of p53 related IncRNAs in irradiation-induced injury, such as epithelial-mesenchymal transition in lung tissue epithelial cells. METHODS: HBEp53-/-cells were established with CRISPR-cas9. Western blotting was used to detect the knockout efficacy of P53 protein, while real time RT-PCR was used to verify the selected expressions of IncRNAs. Bioinformatic analysis including GO and KEGG analysis was used to predict the IncRNA function and signaling pathway. RESULTS: Compared to the irradiated HBE cells, 239 IncRNAs were up-regulated and 289 down-regulated in irradiated HBEp53-/-cells. The top five of the up-regulated or down-regulated differentially expressed IncRNAs were further confirmed by RT-PCR analysis. Through bioinformatic prediction GO analysis, the targeted genes of IncRNAs with changed expressions were related to multiple biological processes and molecular functions, including β3adrenergic receptor binding, protein tyrosine kinase activity, DNA binding, zic ion transmembrane transporter activity, ubiquitin binding and syntaxin binding. KEGG analysis revealed that the functional organismal systems involved included the sensory, nervous, immune, endocrine, environmental adaption, developmental, and circulatory systems. CONCLUSION: p53-related radiation-inducible IncRNAs have been identified in HBEp53-/-cells. These identified IncRNAs may play critical roles in various biological processes and functional signaling pathways in cellular response to radiation injury.
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Objective To establish a simple and convenient method and study the feasibility of using gold nanoparticle composites (ssDNA-AuNPs) for colorimetric detection of gamma radiation.Methods The composites ssDNA-AuNPs were prepared by applying the ssDNA to the surface of AuNPs,and then were irradiated with gamma ray with absorbed doses of 0,5,10,20,and 30 Gy,respectively.Subsequently the color change in the solutions were observed simultaneously with absorption spectra being measured.The linear relationship between the ratio of A625/A521 in the absorption spectrum and the absorbed dose was established.Results With the increase of radiation dose,the color of the solutions changed from wine-red to blue-violet gradually,the ratio of A625/A521 in absorption spectra had excellent liner response for absorbed dose ranging from 0 to 30 Gy,and the linear equation was A625/A521 =0.020 6 + 0.303 6 E(R2 =0.991 5).Conclusions The ssDNA-AuNPs synthesized in this experiment can be successfully used for colorimetric detection of gamma absorbed dose,and a simple and convenient method for detection of gamma radiation has been newly established.
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OBJECTIVE: To observe the in vivo metabolism and distribution characteristics of nano-cerium oxide( nanoCeO_2) in rats,and to explore the radio-protective effect of nano-CeO_2. METHODS: i) A total of 18 specific pathogen free( SPF) SD rats were randomly divided into 3 groups. Rats of experiment group and CeO_2 blood group were gavaged with1. 0 g/kg body weight( bw) nano-CeO_2 suspension. Rats of control group were gavaged with double distilled water( DDW)in equal volume. At different time-points after treatment,venous blood was collected from the rats' eye socket in CeO_2 blood group,meanwhile urine and excrement of rats of experiment group were also collected. Organ and tissue samples of experiment group and control group were collected 24. 0 hours after treatment. The concentrations of cerium in biological samples were detected by inductively coupled plasma mass spectrometry. ii) A total of 72 SPF BALB/c mice were randomly divided into 6 groups. Mice of low-,medium-and high-dose groups were gavaged with 100,300 and 900 mg/kg bw nano-CeO_2 suspension respectively. Mice of negative control group,irradiation control group and drug positive control group were gavaged with DDW in equal volume once daily. After 14 days,mice of the other 5 groups were exposed by60Coγ-rays once with 3. 5 Gy( 1 Gy/min) except the negative control group. Mice of drug positive control group were given intraperitoneal injection with 200 mg/kg bw amifostine half an hour before irradiation. After exposure,mice were treated by the above gavages once daily. After 3 and 8 days,6 mice were randomly selected to collect the peripheral blood for the count of white blood cell( WBC) and lymph cell measuring. RESULTS: i) The cerium concentration in blood reached peak value in 4. 0 hours after exposure of nano-CeO_2,and the cerium concentration of urine and excrement reached maximum in8. 0 hours after exposure. After 24. 0 hours of exposure,the cerium concentration of brain in experiment group was higher than that of control group( P < 0. 05). Among the experiment group,the cerium concentrations of sternum,duodenum and brain were higher than that of kidney and heart( P < 0. 05),meanwhile the cerium concentrations of thymus and lung were higher than that of kidney( P < 0. 05). ii) There was no statistical difference in interactive effect of WBC count and lymph cell counts between nano-CeO_2 exposure ways and time( P > 0. 05). The WBC counts of the low-and medium-dose groups were lower than those of the negative control group and the drug positive control group( P < 0. 05). The WBC count of high-dose group was lower than those of irradiation control group,drug positive control group and medium-dose group( P <0. 05). The lymph cell counts of the 3 dose groups were lower than that of drug positive control group( P < 0. 05).CONCLUSION: The nano-CeO_2 is mainly cumulated in organs such as sternum,duodenum,brain,thymus and lung. After induced by radiation,nano-CeO_2 has a certain degree of promotion role in increasing the WBC counts.
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Objective To investigate the impacts of γ-ray radiation on gene expressions of peripheral blood lymphocytes in SD rats,and to screen differential expression genes and biological pathways closely related to radiation injury.Methods The differential gene expression of peripheral blood lymphocytes in SD rats was selected by microarray at 6 h after 2 Gy 60Co γ-ray exposure in vitro and in vivo.Bioinformatics analysis of the differentially expressed genes was performed by using Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases.Real-time quantitative PCR was applied to verify the screen results of the microarray.Results Fifty-five genes with three times over-expressed level were screened out from the radiation groups both in vitro and in vivo and they were involved in 6 signaling pathways.There were two differentially expressed genes of microarray assay were verified by PCR assay.Conclusions Differential expressed genes in the peripheral blood lymphocytes of SD rats could be induced by γ-ray radiation and they cooperatively contributed to a variety of biological processes.
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Objective To study the correlation of cleft lip and palate transmembrane 1 like(CLPTM1L)expression and radiosensitivity of lung cancer cells.Methods Thiazolyl blue tetrazolium bromide(MTT) and cell colony formation assays were used to determine cell growth and survival.Western Blot assay was employed to measure protein expression.Results The results demonstrated a negative correlation between the CLPTM1L expression level and radiosensitivity of lung cancer cells.A lower radiosensitivity in lung cancer cells containing high level of CLPTM1L expression,and vice versa.Enforced expression of CLPTM1L resulted in a significant reduction of radiosensitivity in lung cancer cells irradiated with γ-rays.On the contrary,a marked elevation of radiosensitivity was observed in lung cancer cells transfected with CLPTM1L siRNA.Conclusions CLPTM1L may be a novel target gene in mediating radiosensitivity of lung cancer cells.
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Objective To study the protective effect of pyrrolidine dithiocarbamate (PDTC) on acute irradiated mice.Methods The 6-8 weeks old male ICR mice were randomly divided into five groups:irradiation alone group (IR),positive control group (amifostine WR-2721 250 mg/kg) and PDTC of 30,60 and 90 mg/kg dose groups.Each group had 10 mice and the drug was given at 0.5 h before whole body irradiation.At 30 d post-irradiation of 7.5 Gy 137 Cs γrays,the mice survival were observed.At 8 d post-irradiation of 5.0 Gy 137 Cs γ-rays,the peripheral blood,hematopoietic system and organ indexes were observed to evaluate the radiation protective effect of PDTC.Results PDTC increased the 30-day survival rates and 60 mg/kg dose had the most obvious effect by increase the survival to 60％ (6/10).The survivals of irradiation alone group and the amifostine positive control group was 10％ (1/10) and 70％ (7/10),respectively.Compared with the irradiation alone group,60 mg/kg PDTC group had the significant difference in spleen index,WBC,HGB,PLT,bone marrow nucleated cells and colony forming unit of spleen (t =2.354,4.793,2.342,6.542,2.649,3.982,P ＜ 0.05).Conclusions PDTC is effective in radiation protection with an optimum dose of 60 mg/kg.
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Objective To measure the difference of radiosensitivity between small and large intestines toward high dose of radiation and investigate the role of stem cells in this difference.Methods C57BL/6 male mice,6-8 weeks old,were randomly divided as control group and radiation group received 19 Gy whole body γ-ray irridiation.Large and small intestines of the mice were collected 6,12,24,48,72 and 96 h after radiation.The proliferation and apoptosis of the large and small intestines and their stem cells were then detected by immunochemistry,and the change of stem cell number in the large and small intestines were detected by in-situ hybridization.Results HE staining showed that 19 Gy γ-ray irradiation caused more severe injury in the small intestine,and all the crypt in the small intestine were extinct at 48 h post-radiation.However,the proliferation index of crypt in the large intestine was as high as 0.23 (t =4.67,P ＜0.05).Compared with the small intestine,the apoptotic index of epithelial cells in the crypt of large intestine was much lower at 12 and 24 h after irradiation (t =-1.92,-2.42,P＜0.05).The apoptotic population of stem cells in the small intestine at 12 and 24 h post irradiation were significantly lower than that in the large intestine (t =-1.98,-2.33,P ＜ 0.05),and the number of stem cell in the large intestine was significantly higher than that in the small intestine 24,48 h after radiation (t =1.98,3.31,P ＜0.05).Conclusions The radiosensitivity of small intestine toward high dose of irradiation is significantly higher than that of the large intestine,where the difference in radiosensitivity of stem cells between large intestine and small intestine may be involved.
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Objective To evaluate the potential feasibility of γ-H2AX foci as a biodosimetry after exposure to ionizing radiation by comparing DNA double-strand break repair kinetics in rat blood lymphocytes with that in human lymphocytes.Methods Peripheral blood lymphocytes separated from Sprague-Dawley(SD) male rats and healthy adults were exposed to γ-rays,and some rats were also subjected to total body irradiation.The inductions of DNA repair-related foci of γ-H2AX,pATM (S1981) and pDNA-PKcs (T2609) were detected with immunofluorescence staining technique at different time points post-irradiation,and the status of their co-localization was analyzed.Results The induction kinetics of γ-H2AX foci in rat lymphocytes was similar to that observed in human lymphocytes.The frequencies of γ-H2AX foci peaked at 30 min after γ-ray irradiation (trst =62.64,th =28.52,P ＜ 0.05),then decreased rapidly after 6 h post-irradiation (trat =45.96,th =14.80,P ＜0.05),and the residual foci number remained only about 3％-8％ of its maximal value at 24 h post-irradiation.At 30 min after γ-ray irradiation,the frequencies of pATM (S1981) and pDNA-PKcs (T2609) foci in rat and human lymphocytes significantly higher than those of nonirradiated control (trat =21.05,25.80,th =11.07,29.52,P ＜ 0.05),and the frequencies of co-localization of pATM (S1981) or pDNA-PKcs (T2609) foci with γ-H2AX foci also markedly increased by 26％-32％ in irradiated lymphocytes of rat and human (trat =5.34,9.14,thuman =18.32,51.28,P ＜0.05).Moreover,γ-H2AX foci incidence in rat lymphocytes in vitro was consistent with that induced by total body irradiation of rat.The number of γ-H2AX foci in irradiated rat lymphocytes increased with irradiation dose in a linear dose-dependent manner,its slope was similar to that of irradiated human lymphocytes reported by other laboratory.Conclusions Rat is a useful animal model to evaluate radiation biodosimetry with γ-H2AX foci in lymphocytes.The co-activation of ATM and DNA-PK plays an important role in DSB repair in the irradiated lymphocytes of rat and human.
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Objective To investigate the dose response of S100A4 gene expression in the irradiated lymphoblastoid cells AHH-1 at different time points post irradiation.Methods AHH-1 cells was exposed to different doses(0,1,3,5,8,10,15 and 18 Gy)of 60Co γ-rays,and its mRNA levels of S100A4 was detected by reverse transcription PCR and real-time PCR at 4,8,12,24,48 and 72 h after irradiation.Results Within the range of applied doses,the level of S100A4 gene expression was upregulated with a good dose-response (R2 =0.79-0.93,P ＜ 0.05) and had obvious difference at different time points (F =8.91,P ＜ 0.01).Conclusion S100A4 gene expression at transcriptional level could be detected easily and had optimum dose-responses at certain time points after irradiation,and hence is applicable as a dosimeter.
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Objective To investigate the effect of salt-induced kinase 2 (SIK2) in the G2/M checkpoint in response to ionizing radiation and the possible mechanism.Methods HeLa cells were irradiated with 60Co γ-rays.The cell model of knockdown SIK2 expression was constrcuted by transfecting HeLa cells with a pSicoR-based lentivirus vector of expressing SIK2 shRNA by lipofectamin 2000.Western blot and flow cytometry were performed to measure the changes of SIK2 protein level and cell cycle distribution.The phosphorylated histone protein H3 on Ser 10 was used as a molecular marker of mitotic cells for detecting the function of G2/M checkpoint.Results The expression level of SIK2 protein increased in HeLa cells after 60Co γ-ray irradiation.A cell model of knockdown SIK2 expression was successfully generated by transfecting the specific shRNA against SIK2.Depression of SIK2 significantly increased the cellular sensitivity at 1,2,4,6 Gy post-irradiation (t =-3.445,-2.581,-3.251,-2.553,P ＜0.05),and led cells to release earlier from the G2/M boundary arrest compared to control cells at 5,6 h post-irradiation (t =4.341,6.500,P ＜ 0.05).Western blot analysis indicated that the irradiation-induced phosphorylated CHK2/T68 in SIK2 knock-down cells was earlier than that in control cells.Conclusions salt-induced kinase 2 (SIK2) participates in the regulation of G2/M checkpoint induced by ionizing radiation and affects cellular radiosensitivity.
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Objective To investigate the changes of serum copper in mice after whole-body irradiation and analyze the feasibility of these changes as a biological dosimeter.Methods Serum copper in mice exposed to 60 Co γ-rays(0,1,2,3,5 Gy) was collected from the orbital of mice and detected with 5-Br-PADAP colorimetric method at 30 min and 7 d after radiation.One-way analysis of variance was used to analyze the difference of serum copper in each group and Dunnett-t test was used to compare the difference between control group and irradiated groups.Linear and quadratic linear fitting function was used to analyze the relationship between serum copper and radiation dose.The change of serum copper was detected at 30 min,1,3,5,7,10,13 and 16 d after radiation to observe the persistence of serum copper.The established relationships were used to estimate the dose in 8 mice irradiated by a blind dose.Results The amount of serum copper in irradiated mice were significantly (F =208.20,145.98,P ＜ 0.05)dependent on the radiation doses with dose responses of y =-0.091x + 0.936 and y =-0.011x2-0.032x + 0.962 (r =0.989,0.995) at 30 min and 7 d post-irradiation,respectively.The concentration of serum copper at 2.0 Gy decreased at 30 min post-irradiation,increased at 1-7 d,then kept at a stable level at 7-14 d even increased slightly after 14 d.With these dose response curves,after radiation with a blind dose of 2 Gy,the absorb doses of mice were assessed to be (1.83-2.25) Gy and (1.82-2.11) Gy at 30 min and 7 d in 95％ confidence interval,respectively.Conclusions The serum copper is a quick,simple,and sensitive biomarker for the early assessment of absorb dose of irradiated mice.
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Objective To investigate the combination effect of curcumin and γ-ray irradiation on PANC-1 cells in vitro.Methods PANC-1 cells were exposed to γ-rays in the presence or absence of curcumin.MTT assay was performed to evaluate cell viability.The expression of P21 was evaluated with RT-PCR and Western blot.Cell cycle distribution and apoptosis were tested by flow cytometry.Results Compared with the γ-ray irradiation group,combination treatment of curcumin and irradiation decreased the cell viability (t =6.72,P ＜ 0.01) and increased the percentage of cells in S-phase (t =4.78,P ＜ 0.05),apoptosis rate (t =6.58,P ＜ 0.01),P21 protein and mRNA expression (t =5.72,5.63,P ＜ 0.01) in PANC-1 cells.Conclusions Curcumin increases the radiosensitivity of PANC-1 cells,which may have clinical implication on radiotherapy of pancreatic cancer.
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Objective To investigate the effect of whole-body irradiation with low-dose γ-rays on the central nervous system of mice.Methods Fifty C57 mice were randomly divided into 3 groups and treated with 0,0.5,1 Gy whole-body irradiation,respectively.24 or 48 h after irradiation,brain tissue of mice was resected and homogenated.The levels of amino acid neurotransmitter,including Glu,Asp,GABA and Gly in brain homogenate were measured by high performance liquid chromatography (HPLC).Results Compared to the brain tissue of untreated mice,the contents of Glu and Asp at 0.5 and 1 Gy (t=-4.080,-3.935,-4.416,-3.630,-4.831, - 4.656,P ＜0.05) in mice brain tissue significantly increased at 24 h at 1 Gy and 48 h.However,the contents of Glu and Asp had no obvious changes in mice brain tissue 24 h after 1 Gy of irradiation. The contents of GABA and Gly had no difference between irradiated groups and untreated control group. Conclusions Short-term whole-body irradiation with low-dose γ-rays induces slight stimulation effect on the central nervous system of mice.
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Objective To study the dose-effect relationship and time-effect relationship of T cell receptor (TCR) gene mutation induced by γ-rays in lymphocytes of human peripheral blood.Methods Samples of peripheral blood were collected from 10 healthy adults and lymphocytes were separated.Four samples from males used to fit time-effect curve were exposed to γ-rays at the doses of 0,0.5,1.0,1.5,2.0,2.5,3.0,3.5,4.0,and 5.0 Gy,respectively,and 6 samples from 3 males and 3 females used to fit dose-effect curves were exposed to γ-rays of the dose of 2 Gy.Flow cytometry was used to detect the mutation frequency of TCR gene (TCR MF).Radiation dose-effect curves and time-effect curves were fitted and optimal mathematical models were selected respectively.Results The optimal mathematical model for radiation dose-effect was quadratic equation model:TCR MF = 92.14 + 22.61D2 (R2adj = 0.65).The optimal mathematical model for radiation time-effect was quadratic polynomial equation model:TCR MF = 3.74 + 743.66T + 308.64T2 (R2adj = 0.79).Conclusions TCR MF is increased as the γ-rayirradiation dose increases within the range of 0-5 Gy,and TCR MF is increased with the lapse of time within the range of 4 days after γ-ray radiation.
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Objective To determine the conditioning regimen suitable for mice allogeneic hematopoietic stem cell transplantation (allo-HSCT).Methods Twelve BALB/c mice were randomly divided into 2 equal groups to undergo X-ray irradiation by linear accelerator at the dose of 7.0 Gy (pure X-ray group) or 60Co source irradiation at the dose of 7.0 Gy (pure γ-ray group).Thirty mice were randomly divided into 2 equal groups to undergo X-ray irradiation and then infusion of bone marrow from donor mice via caudal vein (X-ray + transplantation group) or γ-ray and then infusion of bone marrow via caudal vein (γ-ray + transplahtation group).3,5,7,10,15,20,and 30 d later peripheral blood samples were collected to calculate the number of white blood cells (WBCs) and detect the chimeric rates of lymphocytes by flow cytometry.5,10,and 20 d after irradiation 15 mice were killed with their lung,liver,small intestine,spleen,and femurs taken out to undergo pathological examination.Results The survival rates during the period 5-15 days of the γ-ray + transplantation group were all significantly higher than those of the X-ray + transplantation group.The pathological changes of organs of the X-ray +transplantation group were all more severe than those of the γ-ray + transplantation group.Since the fifth day after transplantation cells originating from the donor began to appear in the peripheral blood.The chimeric rate of the γ-ray + transplantation group 10 days after transplantation was (95.53± 2.57) %.The chimeric rates 5,10,and 20 days after transplantation of the γ-ray + transplantation group were all significantly higher than those of the X-ray + transplantation group (t = 15.263,3.256,P < 0.05).The WBC count of both irradiation groups decreased to the lowest level 5 d later and began to increase 10 days after transplantation and the WBC counts of the γ-ray + transplantation group 10 and 20 days aftertransplantation were both significantly higher than those of the X-ray + transplantation group (t = 3.624,6.695 ,P < 0.05).The chimeric rats of the peripheral lymphocytes 10 and 20 days after transplantation of the γ-ray + transplantation group were both significantly higher than those of the X-ray + transplantation group (t = 12.317,8.295,P < 0.05).The homogeneity rate of transplantation of the γ-ray +transplantation group was better than that of the X-ray + transplantation group.Conclusions As a conditioning regimen in allogeneic hematopoietic stem cell transplantation γ-ray irradiation causes milder injury and accelerated reconstitution of hematopoiesis and immunity,in comparison with X-ray irradiation.
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Objective To investigate the differential expression profiles of microRNAs in the liver of 60Co γ-ray irradiated mice using microRNA microarray and to explore their main functions by bioinformatic analysis.Methods After SPF C57BL/6J mice expose to 4 Gy-single whole body radiation,total number of peripheral WBC and the fMNPCE were measured at 3 d.The differentially expressed miRNAs in mouse liver were detected with miRNA microarray,miRNA-124 and miR-34a were confirmed by real time RT-PCR assay.Bioinformatic analysis was applied to explore target genes and the main functions of the differential expressed miRNAs.Results Compared with control group,the total number of peripheral WBC decreased( t = 2.87,P ＜ 0.05 ) ,while the fMNPCE in bone marrow increased ( t =-2.91,P ＜0.05) after 4 Gy γ-ray irradiation.miRNA microarray revealed that 17 miRNAs were differentially expressed,in which 9 up-regulated,8 down-regulated.The expression levels of miR-124 and miR-34a were coincident with the result of real time RT-PCR.GO analysis showed that some pathways including adherens junction and cell cycle were suppressed,while some immune-related pathways were activated.Conclusions miR-34a and miR-194 were involved in the regulation of acute radiation damage,some other miRNAs including miR-124、miR-382 and miR-92a* also played important roles in radiation process.
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Objective To investigate 60Co γ-ray induced damage in lymphocytes and the relationship between doses of 60Co γ-ray irradiation and the levels of phosphorylated H2AX and ATM.Methods Cells were irradiated with 60Co γ-rays in the range of 0-8 Gy.The levels of phosphorylated H2AX and ATM were detected by Western blot and FACScan,respectively.The micronucleus(MN)was analyzed by CB method to evaluate DNA damage.Results FACScan results showed the dose-effect relationship of γ-H2AX expression were linear.square at 0.5 h post-irradiation to different doses,and the fitting curve was shown as Y=3.96+11.29D-0.45D2.The level of phosphorylated ATM(p-ATM)was not changed significantly by using the same method.Western blot showed that p-ATM protein expression was significandy increased after irradiation compared with sham.irradiated group.The MN assay which represented DNA damage was sensitive to different doses.Conclusions γ-ray irradiation could induce the phosphorylation of H2AX and ATM,which may play an important role in indicating DNA damage.Both of H2AX and ATM have the potential as sensitive biomarker and biodosimeter for radiation damage.
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Objectlve To study the properties of goat tooth enamel electron spin resonance (ESR)dosimetry.Methods Tootll enamel samples of goats were achieved by combined mechanical and chemical treatment at the ages of l,2,3,5,and 6 years.respectively and 9 enamel samples of adult molar were obtained.These enamel samples were exposed to 137Cs γ-rays at the cumulative doses of 0,0.5,1.0,2.0,and 5.0 Gy,respectively.ESR spectra Was measured before and after exposure.Results The background signal of goat tooth samples W88 21.5,significantly lower than that of the adult molar samples(39.5).The dusimetric signal intensity of the goat enamel increased with the radiation dose in a linear manner just as that of the human molars.The average radiation sensitivity of the goat tooth samples was(34.3±1.9)/Gy,close to that of the human tooth samples.Conclusions Goat teeth can be used for retrospective radiation dose reconstruction when human teeth are unavailable,in order to previde scientific data for dose reconstruction accurately.