MiRNA expressions in peripheral blood plasma of workers in a certain mine / 中华放射医学与防护杂志

Objective:To investigate the effect of radon on the expressions of miR-16, miR-106b, miR-449a, let-7g, miR-21, miR-221 and miR-34a in peripheral blood plasma of miners.Methods:A total of 46 randomly selected miners worked underground(the underground group)and 38 miners worked aboveground (the control group). MiRNA levels in the underground and control groups were detected by qRT-PCR and their relationship with cumulative effective dose was further analyzed.Results:The levels of miR-106b, miR-21, miR-221 in plasma of the study group were significantly higher than those in the control group( Z=-2.32, -2.47, -2.79, P<0.05), the corresponding Fc values were 1.61, 1.75, 1.30, respectively. The levels of miR-16, miR-449a, let-7g and miR-34a were slightly higher than those in the control group ( P>0.05). After controlling of confounding factors such as age, BMI and smoking, the alteration of miR-16, miR-106b, let-7g, miR-21 and miR-221 in plasma of the underground group were positively correlated with the cumulative effective dose( t=2.50, 3.31, 2.60, 2.95, 3.25, P<0.05). No significant difference was observed in the plasma levels of miR-449a and miR-34a between the two groups ( P>0.05). Conclusions:miR-106b, miR-21 and miR-221 could be used as potential biomarkers of radon exposure.

Changes of connexin 43 in irradiated human vascular endothelial cells and its influence on cell stiffness / 中华放射医学与防护杂志

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.

Role of connexin 43 in X-ray induced apoptosis in human umbilical vein endothelial cells and its mechanism / 中华放射医学与防护杂志

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.

Protective effects of ferulic acid on mice bone marrow hematopoietic damage induced by irradiation / 中华放射医学与防护杂志

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.

Metabolic characteristics and radio-protective function of nano cerium oxide / 中国职业医学

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.

Dose-effect relationship and time-effect relationship of T cell receptor gene mutation induced by γ-rays in human lymphocytes of peripheral blood / 中华放射医学与防护杂志

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.

Correlation between gene polymorphisms of IL-2,IL-6 and TNF-α in workers exposed to rare earth dust and their lung ventilation function / 中华放射医学与防护杂志

Objective To study the relationship between lung ventilation function of workers exposed to rare earth dust and their IL-2,IL-6 and TNF-α gene polymorphism.Methods TNF-α gene polymorphism were identified by RFLP-PCR,IL-2 and IL-6 gene polymorphisms were identified by PCR-CTPP analysis.Lung ventilation function was deteced by instrument of ventilation function.Results Compared with controls,there was no statistic significance in frequencies distribution of TNF-α gene polymorphism(X2=4.03,P＞0.05),IL-2 gene polymorphism(X2=2.21,P＞0.05)and IL-6 gene polymorphism(X2=1.05,P＞0.05).Compared with IL-2 gene wild type,IL-2 homozygote type increased the risk of lung ventilation dysfunction by 4.29 folds(95% CI 1.09～16.9).Conclusions Compared with controls,incidence of ventilation function of workers exposed to rare earth dust is in ascending trend.IL-2(G/G)gene type induces more serious inflammation reaction than the others.

Preliminary study on serum levels of IL-2, IL-6 and TNF-α and their gene polymorphism in copper miners / 中华放射医学与防护杂志

Objective To study biologic effect of high radon exposure in non-uranium miners by measurements of serum levels of 1L-2, IL-6 and TNF-u and study on their gene polymorphism. Methods Serum levels of IL-2, IL-6 and TNF-αin the miners selected from a Yunnan-based copper mine were measured by ABC-ELISA. TNF-α (-308,G→A) genotypes were identified by RFLP-PCR, IL-2 (-330, T→G) genotypes by sequence analysis. Results Compared the miners with its control group, there were no statistical significance of the concentrations of serum IL-2 (F=0.71, P>0.05), IL-6 (F=1.09, P>0.05) and TNF-α(F=0.95,P>0.05). Frequencies of IL-2 (-330, T→G) genotypes (X2=0.02, P>0.05) and TNF-α(-308, G→A) genotype (x2= 2.21, P>0.05) were shown no statistical significance too. Conclusions Compared with the control group, concentrations of serum IL-2, IL-6 and TNF-n in miners working in the copper mine was lower, frequencies of genotypes of TNF-o (-308,A/A) was higher in the miners. But all the differences were not statistical significant.