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Objective:To investigate the changes of connexin 43 (Cx43) in human umbilical vein endothelial cells (HUVEC) after X-ray irradiation and its influence on the stiffness of irradiated cells.Methods:Western blot was used to detect the expression of Cx43 in HUVEC cells at different time points (0, 6, 12, 24 and 48 h) after different doses of X-ray irradiation (0, 2.5, 5, 10 and 20 Gy), and the phosphorylation levels of three phosphorylation sites (Ser279/282, Ser368 and Tyr265) of Cx43 at different time points (3, 6, 24 and 48 h) after 0, 5 and 10 Gy irradiation. The distribution of Cx43 protein in the irradiated HUVEC cells was detected by immunofluorescence. The stiffness changes of cells were detected by atomic force microscopy (AFM) at the depths of 50, 100 and 200 nm.Results:The expression of Cx43 in HUVEC cells was reduced at 6, 12, 24 and 48 h after 10 Gy X-ray irradiation( t=3.262, 3.708, 3.686, 6.825, P<0.05)and this decrease had a dose dependent manner at 24 h after 2.5, 5, 10 and 20 Gy irradiation ( t=3.034, 10.720, 13.130, 13.650, P<0.05). At 24 h after 5, 10 and 20 Gy X-ray irradiation, the distribution of Cx43 in HUVEC cells was transported from intercellular gap junctions to nucleus and perinuclear region. At 24-48 h after irradiation, the phosphorylation level of Ser368 at Cx43 increased and in a dose dependent manner. At 24 h after irradiation, the stiffness of the irradiated cells decreased significantly under the conditions of 100 and 200 nm ( t=3.362, 5.122, P<0.05), and recovered with overexpression of Cx43 ( t=2.674, 4.398, P<0.05). Conclusions:X-ray irradiation leads to the phosphorylation of Ser368 at Cx43, which promotes the degradation and nucleus/perinuclear translocation of Cx43 and reduces the stiffness of HUVEC. Increasing the expression level of Cx43 is helpful to the stiffness recovery of irradiated vascular endothelial cells, suggesting that Cx43 may be a potential target for regulating radiation injury of vascular endothelial cells.
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OBJECTIVE@#Pyroptosis is an inflammatory form of programmed cell death. This phenomenon has been recently reported to play an important role in radiation-induced normal tissue injury. Connexin43 (Cx43) is a gap junction protein that regulates cell growth and apoptosis. In this study, we investigated the effect of Cx43 on X-ray-induced pyroptosis in the human umbilical vein endothelial cells (HUVECs).@*METHODS@#HUVECs, Cx43 overexpression, and Cx43 knockdown strains were irradiated with 10 Gy. Proteins were detected using western blot analysis. Cell pyroptosis was evaluated using the fluorescence-labeled inhibitor of caspase assay (FLICA) and propidium iodide staining through flow cytometry and confocal microscopy. Cell morphology and cytotoxicity were detected by scanning electron microscopy and lactate dehydrogenase release assay, respectively.@*RESULTS@#Irradiation with 10 Gy X-ray induced pyroptosis in the HUVECs and reduced Cx43 expression. The pyroptosis in the HUVECs was significantly attenuated by overexpression of Cx43 as it decreased the level of active caspase-1. However, interference of Cx43 expression with siRNA significantly promoted pyroptosis by increasing the active caspase-1 level. Pannexin1 (Panx1), a gap junction protein regulates pyroptosis, and its cleaved form is used to evaluate channel opening and active state. The level of cleaved Panx1 in the HUVECs and Cx43 knockdown strains increased in the presence of X-ray, but decreased in the Cx43 overexpression strains. Furthermore, interference of Panx1 with siRNA alleviated the upregulation of pyroptosis caused by Cx43 knockdown.@*CONCLUSION@#Results suggest that single high-dose X-ray irradiation induces pyroptosis in the HUVECs. In addition, Cx43 regulates pyroptosis directly by activating caspase-1 or indirectly by cleaving Panx1.
Subject(s)
Humans , Caspase 1 , Genetics , Metabolism , Connexin 43 , Genetics , Metabolism , Connexins , Genetics , Metabolism , Gene Expression Regulation , Radiation Effects , Human Umbilical Vein Endothelial Cells , Physiology , Radiation Effects , Nerve Tissue Proteins , Genetics , Metabolism , Pyroptosis , X-RaysABSTRACT
Objective To study the role of Cx43 in X-ray induced apoptosis of HUVEC cells and its mechanism.Methods Flow cytometry was used to detect the apoptosis of HUVEC cells at 48-96 h after 10 Gy X-ray irradiation and at 72 h after irradiation of different doses.Western blot was used to detect the protein expressions of Cx43 and cleaved caspase-3 in HUVEC cells at 72 h after 0,5,10 and 20 Gy irradiation.Small interfering RNA was transfected into HUVEC cells to silence Cx43 expression,the Cx43 bearing plasmid was transfected into cells to overexpress Cx43.The effect of Cx43 knockdown or overexpression on apoptosis induction and cleaved caspase-3 protein expression were detected by flow cytometry and Western blot,respectively.Results The apoptosis of HUVEC increased significantly from 48 h to 96 h after X-ray irradiation and in a dose-dependent manner at 72 h after irradiation.The expression of Cx43 protein was negatively correlated with the dose but the expression of cleaved caspase-3 was positively correlated with the dose in the range of 0-20 Gy.After Cx43 silencing,the proportion of early apoptosis and apoptosis combined with dead cells were significantly higher than that of the siRNA control group(t =3.674,6.375,P ＜ 0.05).After Cx43 overexpression,the proportion of early apoptosis and apoptosis combined with dead cells were significantly lower than that of vector control group(t =9.399,11.190,P ＜ 0.05).The expression of cleaved caspase-3 in the Cx43 silencing group was higher than that in the siRNA control group,but this protein in the Cx43 overexpressed group was lower than that in the vector control group.Conclusions Cx43 may protect X-ray irradiated HUVEC cells from apoptosis by down-regulating the activation of caspase-3.
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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 observe the effect and the mechanisms of ferulic acid on radiationinduced damage of mice peripheral blood and bone marrow hematopoietic function.Methods Ninety-six mice were randomly divided into sham irradiation group,irradiation group,positive drug group and 10,30,90 mg·kg-1 ·d-1 ferulic acid group,16 mice per group.Mice were exposed to 3.5 Gy γ-rays 24 h after first drug taken.Then,mice were given drugs for 7 d after irradiation.White blood cells in peripheral blood of 10 mice per group were counted 2 d before irradiation and 3,7,10,15 and 22 days after irradiation.The bone narrow of the other six mice was taken to detect the micronuclei frequency of polychromatic erythrocyte,the hematopoietic progenitor cell colony formation capacity,Thbd and HMGB1 protein expressions in mice bone marrow on the seventh day after irradiation.Results Compared with the irradiation alone group,the treatment of mice with ferulic acid 90 mg· kg-1 · d-1 increased the number of white blood cells in peripheral blood at 3,10,15 and 22 d after irradiation (t =2.267,2.399,1.945,2.828,P ＜ 0.05).Treatment with mice with ferulic acid 90 mg· kg-1 · d 1 decreased the micronuclei rate of erythrocytes in irradiated bone marrow (t =4.013,P ＜ 0.05),increased the clone numbers of CFU-E,BFU-E and CFU-GM of hematopoietic progenitor cells (t =2.366,2.953,3.115,P ＜0.05),improved the relative expression of the Thbd protein in bone marrow and the HMGB1 protein in nuclear (t =17.75,23.39,P ＜ 0.01).Conclusions Ferulilc acid could protect the bone marrow hematopoietic of mice exposed to irradiation by regulating the expressions of Thbd and HMGB1 protein,and then accelerate the peripheral cells recovery.
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Objective To investigate the mechanism of malignant transformation in human bronchial epithelial cell line BEP2D exposed to α-particles.Methods The levels of intracellular ROS and malonaldehyde (MDA) in BEP2D,RH22 (passage 22 of α-particle-irradiated BEP2D cells) and BERP35T-1 cells (derived from nude mice bearing malignant transformed cells generated from the passage 35 of α-particle-irradiated BEP2D cells) were assayed with DCFH-DA and MDA kit,respectively.The expressions of 8-OH-dG and γ-H2AX in BEP2D,RH23 (passage 23 of α-particle-irradiated BEP2D cells)and BERP35T-1 cells were also measured with immunocytochemistry and immunofluorescence staining.Results Compared to BEP2D cells,the levels of ROS ( t =4.30 and 3.94,P ＜ 0.05 ) and MDA ( t =4.89 and 15.10,P ＜0.05) increased in RH22 and BERP35T-1 cells.The expressions of 8-OH-dG (t =3.80 and 2.92,P ＜ 0.05 ) and γ-H2AX ( t =7.61 and 12.67,P ＜ 0.05 ) in RH23 and BERP35T-1 cells were also higher than those in BEP2D cells.Conclusions Oxidative stress induces lipid peroxidation and DNA damage leading to genomic instability,which could contribute to cellular malignant transforming process in the human bronchial epithelial cell line BEP2D with α-particle exposure.
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Objective To investigate the antioxidant ability and radiosensitivity in the malignant transformed human bronchial epithelial cell line BEP2D induced by α-particle exposure.Methods Glutathione Peroxidase (GPX),Catalase (CAT) and Glutathione (GSH) assay kits were employed to detect GPX and CAT enzyme abilities and the levels of GSH in BEP2D,RH21 ( passage 21 of α-particle-irradiated BEP2D cells),and BERP35T-1 cells (derived from nude mice bearing malignant transformed cells generated from cells of passage 35 of α-particle-irradiated BEP2D cells).MTT assay were used to test the growth rate of BEP2D,RH21 and BERP35T-1 cells treated with 0,30,60,90,120,and 150 μmoL/L H2O2.Colony-forming test and MTT assay were used to examine the cell survival fraction and the growth rate of BEP2D,RH21 and BERP35T-1 cells exposed to 0,2,4,and 8 Gy of γ-rays,respectively.Results GPX and CAT enzyme activities in RH21 and BERP35T-1 cells were obviously lower than in BEP2D( t = 5.75-67.92 ,P ＜ 0.05 ).CAT enzyme activity in BERP35T-1 was lower than that in RH21 cells (t =22.25 ,P ＜0.01 ).Compared to BEP2D cells,decreased level of GSH was detected in BERP35T-1 cells(t = 7.76,P ＜ 0.05 ),but there was no change in RH21.After treatment with 30,60,90,120,and 150 μmol/L H2O2,the growth rates of BEP2D were all higher than those of BERP35T-1 cells(t = 10.37-58.36,P ＜0.01 ).Meanwhile,the growth rates of BEP2D were all higher than those of RH21 cells after treatment with 60,90,120,and 150 μ mol/L H2O2 (t = 29.90-84.68,P ＜ 0.01 ).In addition,compared to BEP2D cells,decreased cell survival fraction and growth rate of BERP35T-1 cells were observed after irradiation with 2,4,and 8 Gy of y-rays ( t = 5.87-34.17,P ＜ 0.05 ).The cell survival fraction and growth rate of RH21 were all lower than those of BEP2D cells at 4 and 8 Gy post-irradition( t =6.33- 45.00,P ＜ 0.05 ).Conclusion The function of antioxidant system decreased in the α-particleinduced transformed cells,which could contribute to the acceleration of cellular malignant transforming process and radiosensitivity.
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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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<p><b>OBJECTIVE</b>To investigate whether the deletion of PTEN affects the expression of Cu/Zn SOD and the related biology.</p><p><b>METHODS</b>Protein and mRNA expression levels of PTEN, P-Akt, Cu/Zn SOD in the control immortalized wild type mouse embryonic fibroblast cells (PTEN+/+) and PTEN-null cells (PTEN-/-) were evaluated by Western blot and Northern blot respectively. The level of superoxide anions were detected using fluorescent probes. The DNA damage was documented by single cell alkalescence gel assay. MTT was used to study the effect of H2O2 on the proliferation of cells.</p><p><b>RESULTS</b>The expression of Cu/Zn SOD was down regulated at both protein and mRNA levels, and the level of superoxide anions increased in the PTEN-null cells (PTEN-/-). The phosphorylation level of Akt kinase was up-regulated and the antiproliferative effect of H2O2 decreased in PTEN-/- cells. Furthermore, DNA damage was observed significantly severer in both the blank control and H2O2 treated groups than that in the PTEN+/+ cells.</p><p><b>CONCLUSIONS</b>Deletion of PTEN affects the expression of Cu/Zn SOD. As a result, reactive oxygen species (ROS) keep at a high level, along with decrease of accumulated oxidative damage and the antiproliferative effect of ROS.</p>
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Animals , Mice , Copper , Chemistry , Down-Regulation , Fibroblasts , Pathology , Gene Expression Regulation , Genetics , Hydrogen Peroxide , Metabolism , Mice, Knockout , PTEN Phosphohydrolase , Genetics , Phosphorylation , Reactive Oxygen Species , Sequence Deletion , Superoxide Dismutase , Genetics , Metabolism , Zinc , ChemistryABSTRACT
<p><b>OBJECTIVE</b>To isolate Japanese encephalitis virus (JEV) from mosquitoes collected in Liaoning province and analysis the genotype of new isolated JEV strains and the characters of nucleotide and amino acid in the E gene.</p><p><b>METHODS</b>Collected mosquitoes in Dandong Liaoning Province in August, 2006. Virus isolation was using issue culture cells. Isolated viruses were identified by using serological and molecular methods.</p><p><b>RESULTS</b>Two new JEV strains, LNDG07-02 and LNDG07-16, were isolated from 1500 mosquitoes were belonging to genotype 1. The identity of nucleotide and amino acid of E gene between new JEV strains and live attenuated vaccine strain SA14-14-2 were 87.8-88% and 97.2%, respectively. Total 11 amino acid sites were differences in E gene between new isolates and SA14-14-2. However, there were no differentiation between the new JEV strains and the isolates in Donggang 2002.</p><p><b>CONCLUSION</b>Genotype 1 JEV was isolated again from Donggang, since the first isolation of this genotype in 2002. Genotype 1 JEV continues in existence in Donggang Liaoning Province.</p>
Subject(s)
Animals , Female , Male , Mice , Amino Acid Sequence , Brain , Pathology , Virology , Cell Line , China , Epidemiology , Culicidae , Virology , Encephalitis Virus, Japanese , Classification , Genetics , Encephalitis, Japanese , Epidemiology , Virology , Genotype , Insect Vectors , Virology , Molecular Sequence Data , Phylogeny , RNA, Viral , Genetics , Sequence Analysis, DNAABSTRACT
Objective To study the effect of TGF-?1 on the activation of ERK MAPK in human bronchial epithelial BEP2D cells. Methods Western blot was employed to examine the time-dependent activation of ERK MAPK by TGF-?1. BEP2D cells were harvested after treatment of human bronchial epithelial cells with 2 ng/ml TGF-?1 for 0, 10, 30, 60, 120, 240 and 480 min, respectively. Fluorescent dye staining and flow cytometry were employed to assess the apoptosis of BEP2D cells treated with vehicle, or with 2ng/ml TGF-?1, or co-treated with 2ng/ml TGF-?1 and 5?M U0126. Proliferation of BEP2D cells treated with vehicle, or with 2ng/ml TGF-?1 or 5?M U0126, or co-treated with 2ng/ml TGF-?1 and 5?M U0126 was assayed with colony-forming test, respectively. Morphological observation was performed to observe the morphological changes in BEP2D cells treated with vehicle, or with 5ng/ml TGF-?1 or 5?M U0126, or co-treated with 5ng/ml TGF-?1 and 5?M U0126, respectively. Results TGF-?1 activated ERK MAPK in BEP2D cell. The maximal activation of ERK MAPK took place at 60min after stimulation with 2ng/ml TGF-?1. TGF-?1 treatment effectively inhibited cell proliferation, and induced their apoptosis and epithelial-mesenchymal transition. Pretreatment with U0126, an inhibitor of ERK MAPK, significantly enhanced the TGF-?1-mediated anti-proliferation and apoptosis effects, and inhibited the effect of epithelial-mesenchymal transition of TGF-?1 in BEP2D cells. Conclusion TGF-?1-induced phosphorylation of ERK MAPK may participate in BEP2D cell proliferation and apoptosis regulation.