Objective To evaluate the therapeutic effect of normal mouse serum on radiation pneumonitis in mice and explore the possible mechanism.Methods Mouse models of radiation pneumonitis induced by thoracic radiation exposure were given intravenous injections of 100 μL normal mouse serum or normal saline immediately after the exposure followed by injections once every other day for a total of 8 injections.On the 15th day after irradiation,histopathological changes of the lungs of the mice were examined using HE staining,the levels of TNF-α,TGF-β,IL-1α and IL-6 in the lung tissue and serum were detected using ELISA,and the percentages of lymphocytes in the lung tissue were analyzed with flow cytometry.High-throughput sequencing of exosome miRNA was carried out to explore the changes in the signaling pathways.The mRNA expression levels of the immune-related genes were detected by qRT-PCR,and the protein expressions of talin-1,tensin2,FAK,vinculin,α-actinin and paxillin in the focal adhesion signaling pathway were detected with Western blotting.Results In the mouse models of radiation pneumonitis,injections of normal mouse serum significantly decreased the lung organ coefficient,lowered the levels of TNF-α,TGF-β,IL-1α and IL-6 in the serum and lung tissues,and ameliorated infiltration of CD45+,CD4+and Treg lymphocytes in the lung tissue(all P<0.05).The expression levels of Egfr and Pik3cd genes at both the mRNA and protein levels and the protein expressions of talin-1,tensin2,FAK,vinculin,α-actinin and paxillin were all significantly down-regulated in the mouse models after normal mouse serum treatment.Conclusion Normal mouse serum ameliorates radiation pneumonitis in mice by inhibiting the expressions of key proteins in the Focal adhesion signaling pathway.

Objective To evaluate the therapeutic effect of normal mouse serum on radiation pneumonitis in mice and explore the possible mechanism.Methods Mouse models of radiation pneumonitis induced by thoracic radiation exposure were given intravenous injections of 100 μL normal mouse serum or normal saline immediately after the exposure followed by injections once every other day for a total of 8 injections.On the 15th day after irradiation,histopathological changes of the lungs of the mice were examined using HE staining,the levels of TNF-α,TGF-β,IL-1α and IL-6 in the lung tissue and serum were detected using ELISA,and the percentages of lymphocytes in the lung tissue were analyzed with flow cytometry.High-throughput sequencing of exosome miRNA was carried out to explore the changes in the signaling pathways.The mRNA expression levels of the immune-related genes were detected by qRT-PCR,and the protein expressions of talin-1,tensin2,FAK,vinculin,α-actinin and paxillin in the focal adhesion signaling pathway were detected with Western blotting.Results In the mouse models of radiation pneumonitis,injections of normal mouse serum significantly decreased the lung organ coefficient,lowered the levels of TNF-α,TGF-β,IL-1α and IL-6 in the serum and lung tissues,and ameliorated infiltration of CD45+,CD4+and Treg lymphocytes in the lung tissue(all P<0.05).The expression levels of Egfr and Pik3cd genes at both the mRNA and protein levels and the protein expressions of talin-1,tensin2,FAK,vinculin,α-actinin and paxillin were all significantly down-regulated in the mouse models after normal mouse serum treatment.Conclusion Normal mouse serum ameliorates radiation pneumonitis in mice by inhibiting the expressions of key proteins in the Focal adhesion signaling pathway.

Objective:To investigate the effects of tetrabromobisphenol A (TBBPA) on ionizing radiation (IR)-induced liver toxicity based on a zebrafish model and provide a scientific basis for assessing microplastic-radiation exposure hazards to the survival and health of aquatic organisms and humans.Methods:Healthy adult zebrafish aged 4-6 months were grouped (20 fish each group, sex in half) by random number table method in three different ways. The TBBPA exposure concentration screening experiment was divided into 4 groups: control group and TBBPA (3, 30 and 300 μg/L) treatment groups. The experiment of effects of double exposure on liver function was divided into 5 groups: control group, IR (10, 20 or 30 Gy) groups and IR+ TBBPA (60, 300 and 1 500 μg/L) treatment groups. The experiment of effects of TBBPA on hepatic radiation toxicity was divided into 3 groups: control group, IR (20 Gy) group, and IR+ TBBPA (300 μg/L) group. The changes in liver function indexes, oxidative stress markers, pro-inflammatory cytokines, and liver cell apoptosis were monitored, differential metabolic pathways and metabolites were identified upon untargeted metabolomics assays, and inter-group data were compared by One-way ANOVA test.Results:The activities of ALT and AST in zebrafish liver increased in a dose-dependent manner after exposure to TBBPA, and the differences between 300 μg/L TBBPA group and control group were statistically significant ( t=-2.22, -3.20, P<0.05). IR at a dose of 20 Gy or above induced a significant decline of liver function, and at this radiation dose, combined exposure to 300 μg/L or above TBBPA intensified the liver toxicity (compared with the control group, t=-8.18 to -4.63, P<0.05, compared with IR group, t=-5.22 to -0.30, P < 0.05). Compared with the control group, the activities of ALT and AST, levels of ROS, MDA and SOD, mRNA and protein expression levels of TNF-α, IL-1β, Cox-2, Caspase-8 and Caspase-9, and cell apoptosis in zebrafish livers of IR and IR+ TBBPA groups increased gradually (compared with the control group, t=-12.29 to -2.88, P<0.05, compared with IR group, t=-4.40 to -2.31, P<0.05). The differences in the content of D-gluconic acid, p-cresol and other metabolites in liver tissues were more and more significant among the three groups, involving multiple KEGG pathways such as biosynthesis, degradation and metabolism. Conclusions:Exposure to 300 μg/L TBBPA can aggravate IR-induced liver toxicity of zebrafish, which involves the mechanism that further elevates the levels of oxidative stress, inflammation, and apoptosis, as well as radiation-induced liver metabolic disorders.

Objective:To elucidate the change of whole genome expression profile for the effect of melatonin on radiation-induced intestinal injury in mice.Methods:C57BL/6J male mice were administrated with melatonin at 10 mg/kg body weight by intraperitoneal injection once a day for five consecutive days before abdominal irradiation with 14 Gy of γ-rays. Small intestines were harvested 3 d after radiation. GO annotation and KEGG pathway of the differential genes involved in small intestine were explored by DNA microarray analysis.Results:Compared with the control group, 584 differential genes were up-regulated and 538 differential genes were down-regulated for administration group pre-irradiation. The overlapping differential genes were selected from the irradiated mice and the administrated mice pre-irradiation. There were 324 up-regulated genes and 246 down-regulated genes unique to the administrated mice pre-irradiation. GO annotation analysis of the differential genes indicated that the top 15 significantly enriched biological processes for the administrated mice pre-irradiation mainly included autophagosome assembly (GO: 0000045), autophagosome organization (GO: 1905037) and regulation of acute inflammatory response (GO: 0002673). The genes ATG12, ATG16L2 and AMBRA1 were involved in autophagosome assembly and autophagosome organization. The genes C3, CPN1, CD55, CFP, CNR1, C1QA, C2 and CREB3L3 were involved in the regulation of acute inflammation response. KEGG pathway analysis of the differential genes involved indicated that the top 15 significantly enriched pathways for the administrated mice pre-irradiation mainly included O-glycan biosynthesis (hsa00512), glycosphingolipid biosynthesis (hsa00603), ECM-receptor interaction (hsa04512) and biosynthesis of unsaturated fatty acids (hsa01040). qRT-PCR verification showed that the expressions of ATG12 and ATG16L2 genes involved in autophagy for the administrated mice pre-irradiation increased significantly compared with the irradiated mice ( t=2.40, 4.35, P<0.05). Conclusions:The differential genes related with the biological process of autophagy, acute inflammatory response and the pathway of unsaturated fatty acid biosynthesis might be involved in the effect of melatonin on radiation-induced intestinal injury.

Objective:To investigate the effect of miR-27b-3p on radiation resistance of breast cancer cells.Methods:The relative expression levels of miR-27b-3p in normal tissues and breast cancer tissues were analyzed through GEO database and verified by the qRT-PCR assay. Cloning formation, immunofluorescence, and EDU assay were used to assess the functions of miR-27b-3p on radioresistance of breast cancer cells. The luciferase reporter assay was used to verify whether miR-27b-3p directly targeted PLK2 mRNA. A rescue experiment was performed to identify the influence of PLK2 overexpression on miR-27b-3p regulated radioresistance.Results:The expression level of miR-27b-3p in both breast cancer tissues ( t=2.99, P<0.01) and breast cancer cells ( t=21.21, 32.88, P<0.05) was significantly higher than those in normal breast tissues and cells, especially, it was elevated in radioresistant MCF-7R cells ( t=25.63, P<0.05). Overexpression of miR-27b-3p enhanced the cloning efficiency of MCF-7 cells ( t=10.32, P<0.05), and had a protective effect on the proliferation of irradiated MCF-7 cells ( t=8.77, 8.26, 8.03, P<0.05). But interference of miR-27b-3p reduced the cloning efficiency and proliferation of MCF-7R cells ( t=40.00, P<0.05) after irradiation with different doses( t=8.54, 8.32, 8.23, P<0.05). Moreover, PLK2 was verified to be a direct target of miR-27b-3p, and overexpression of PLK2 inhibited miR-27b-3p-mediated radioresistance of breast cancer cells (MCF-7: t=9.66, P<0.05; MCF-7R: t=6.42, P<0.05). Conclusions:miR-27b-3p contributes to the radioresistance of breast cancer cells by targeting PLK2.

Objective:To confirm the mechanism of Sedum alfredii extract (SafE) alleviating radiation injury in human small intestinal epithelial cells (HIEC-6). Methods:HIEC-6 cells were divided into 4 groups, including control group (Con), irradiation group (IR), SafE alone group (SafE) and SafE plus irradiation group (SafE+ IR). All of the SafE groups were treated with 0.02 g/ml (W/V) SafE for 24 h. Cell viability (CCK-8 method ) and intracellular ROS levels were investigated at 24 h after 2, 4, and 6 Gy irradiation. Samples were taken at 24 h after 4 Gy irradiation for transcriptome analysis, and the intracellular E3 ubiquitin ligase PRKN expression level was measured. The thickness of endoplasmic reticulum was detected at 24 h after 4 Gy irradiation using fluorescent dye.Results:SafE could maintain cell viability after irradiation ( t=2.94-10.40, P<0.05), and significantly reduced the level of ROS in the irradiated cells ( t=-13.29--4.53, P<0.05). PRKN was preliminarily verified to be the target gene of SafE that maintained PRKN transcript level and endoplasmic reticulum thickness after irradiation (IR group vs. Con group: t=-5.55, 3.27, P<0.05, SafE group vs. SafE+ IR group: P>0.05). Conclusion:SafE is effective in maintaining ER thickness and reducing cellular radiation damage and its target gene PRKN could be regulated by ionizing radiation.

Objective:To study the effect of emulsifier Tween-80 on radiation-induced bile acid enterohepatic circulation disturbance and the treatment strategy.Methods:Male C57BL/6 J mice were randomly divided into healthy control group, radiation-only group, radiation + Tween-80 group and radiation + Tween-80 + butyric acid group. The mice were exposed to total abdominal irradiation (TAI) using a specific steel lead chamber and γ-ray irradiator was used throughout the experiments. Mice in radiation+ Tween-80 group and radiation+ Tween-80+ butyric acid group were intragastrically administrated with Tween-80 for 7 d before irradiation, while healthy control group and radiation-only group were treated with sterile water. After irradiation, butyric acid was administrated to mice in radiation+ Tween-80+ butyric acid group until euthanasia, while healthy control group, radiation-only group and radiation+ Tween-80 group were treated with sterile water until euthanasia. Small intestine and fecal particles were collected 21 d after irradiation. The concentrations of bile acid in small intestinal and fecal samples were measured using enzyme linked immunosorbent assay (ELISA), the expression of TGR5 and JAM-A, as well as the ratio of IL-10/IL-12 in intestine were detected by quantitative real-time PCR (qRT-PCR). The expression levels of GPR43 in the colon were compared using immunohistochemistry (IHC).Results:Tween-80 pretreated mice exhibited lower concentration of bile acid in small intestine and higher level of bile acid in fecal sample after irradiation (7.92%, 7.99%, t=3.93, 2.94, P<0.05), the expression of TGR5, which mediating the biological function of bile acid, and it′s downstream JAM-A gene were down-regulated (20.93%, 9.91%, t=4.85, 5.14, P<0.05), the ratio of IL-10/IL-12 (indicator related to inhibition of inflammation) (4.59%, t=3.39, P<0.05) as well as the expression of GPR43 protein, a G-protein-coupled receptor for butyric acid, decreased in the colon of Tween-80-pretreated mice compared with the radiation-only group. ELISA assay revealed that butyric acid administration elevated bile acid level in small intestines (8.06%, t=9.25, P<0.05), but reduced that in feces (14.41%, t=4.71, P<0.05). In addition, TGR5 and JAM-A showed higher expression in the intestine of butyric acid-treated mice (19.35%, 32.71%, t=7.69, 19.23, P<0.05), as well as the ratio of IL-10/IL-12 (2.39%, 4.05%, t=3.38, 5.92, P<0.05) and the content of GPR43 protein in colon. Conclusions:Tween-80 deteriorates the disturbance of bile acid enterohepatic circulation induced by ionizing radiation in mice. Butyric acid administration erases the adverse effects of Tween-80.

Objective:To study the effect of fasting on 137Cs γ-ray radiation-induced intestinal injury in mice, and to explore the effect of fasting on fecal metabolites of mice through non-targeted metabolomics. Methods:C57BL/6 mice were divided into healthy control group, 9 Gy γ-ray whole body irradiation (WBI)/ 15 Gy γ-ray whole abdominal irradiation (WAI) group, fasting (24 h, 48 h, 72 h)+ 9 Gy WBI/ 15 Gy WAI group. After irradiation, the survival rate, spleen index and thymus index were calculated. C57BL/6 mice in non-target metabolism experiment were randomly divided into four groups: control group, fasting 24 h group, 15 Gy γ-ray WAI group, fasting 24 h + 15 Gy γ-ray WAI group, 6 mice in each group. After 15 Gy WAI, the feces of mice in each group were collected at 3.5 days for non-targeted metabolomics detection.Results:The median survival time of mice with 48 h and 24 h fasting before 9 Gy γ-ray irradiation was increased by 1 day and 4 days, and the survival rates of mice treated with 48 h and 24 h fasting before 15 Gy WAI were 16.67% and 25%, respectively. 15 Gy γ-ray WAI on mice with fasting for 24 h before irradiation could increase the body weight ( t=2.338, P=0.042) and spleen index ( t=2.289, P=0.045) at 3.5 days after irradiation. Through non-targeted metabonomic analysis, it was found that there were 30 differentially expressed metabolites in fecal samples of fasting and non-fasting mice subjected to WAI, and metabolic pathway enrichment analysis showed that there was an imbalance in the metabolic pathway of steroid biosynthesis. Conclusions:Fasting before irradiation can improve the survival rate of mice with intestinal radiation injury and change their intestinal metabolites, suggesting that pre-irradiation fasting or short-term dietary nutrition changes are involved in the regulation of intestinal radiation damage.

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.

Tissue inhibitor of metalloproteinases-2 (TIMP-2) inhibits tumor migration and invasion. Obtaining TIMP-2 protein is conducive to a comprehensive and in-depth study of its function and mechanism in tumorigenesis and development. We collected human TIMP-2 protein through prokaryotic expression in vitro. We expressed, purified and characterized human TIMP-2 protein. First, the human TIMP-2 gene was cloned from the cDNA obtained by reverse transcription of total RNA of human lung cancer A549 cells, and constructed to pET28a vector. The recombinant plasmid pET28a-TIMP-2 was transformed into Escherichia coli BL21(DE3) after restriction endonuclease digestion and sequencing analysis. The expression of TIMP-2 protein was induced by isopropyl-β-D-thiogalactoside (IPTG), and the expression conditions were optimized. After purification by nickel affinity column, the fusion protein His-TIMP-2 was identified by Western blotting method and its biological activity was detected by gelatin zymography. The fusion protein His-TIMP-2 existed in the form of inclusion body in E. coli. In a certain range, the concentration of IPTG had no significant effect on the expression amount of His-TIMP-2. But in this expression system, induction temperature and time were the key parameters, and the expression amount of His-TIMP-2 in E. coli increased with the increase of induction temperature. The purified and refolded fusion protein could effectively inhibit the activity of matrix metalloproteinases expressed by human lung cancer A549 cells. The acquisition of active fusion protein lays a foundation for further study of the function and mechanism of human TIMP-2, and is of great significance for tumor therapy.
Cloning, Molecular ; Escherichia coli/genetics* ; Humans ; Recombinant Fusion Proteins/genetics* ; Recombinant Proteins ; Tissue Inhibitor of Metalloproteinase-2/genetics*