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OBJECTIVE To explore the protective mechanism of amifostine on acute radiation injury mice. METHODS Thirty C57BL/6J mice were randomly divided into normal control group， model group and amifostine group （150 mg/kg）， with 10 mice in each group. Thirty minutes before irradiation， the mice in the amifostine group were intraperitoneally injected with amifostine； normal control group and model group were given constant volume of normal saline intraperitoneally； then acute radiation injury was induced by 4 Gy X-ray radiation in both model group and amifostine group. The white blood cell count （WBC）， platelet count and red blood cell （RBC） count in mice were detected 2 hours before irradiation and on days 1， 4， 7， 10 and 14 after irradiation； the changes in the proportion of WBC （neutrophils， lymphocytes and monocytes） on the 7th day after irradiation were analyzed. The 16S rRNA high-throughput sequencing was used to analyze the structure of gut microbiota in mice feces on the 7th day after irradiation， then its correlation with WBC was analyzed. RESULTS The counts of WBC on the 1st， 4th， 7th and 10th day after irradiation， platelet count on the 10th day after irradiation and RBC count on the 1st day after irradiation in the amifostine group were significantly higher than those in model group （P＜0.05）. Compared with normal control group，β diversity of gut microbiome showed significant change， relative abundance of Firmicutes increased and that of Bacteroidetes decreased in model group. Amifostine could reverse the change in β diversity of gut microbiome， and the relative abundance of Bacteroidetes and Firmicutes. The model group consisted of four distinct species， namely Allobaculum， Erysipelotrichia， Erysipelotrichales and Erysipelotrichaceae， which were significantly negatively correlated with the proportion of peripheral blood lymphocytes （P＜0.01）； amifostine group consisted of two distinct species， namely Lactobacillus murinus and L. crispatus， which were significantly negatively correlated with the proportion of neutrophils （P＜0.05）. CONCLUSIONS Amifostine significantly improves irradiation-induced injury by regulating dysbiosis of LY201816） gut microbiota.
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Objective To investigate the radioresistant effects of pprI gene of Deinococcus radiodurans on BALB/c mice.Methods Male BALB/c mice in SPF level were applied for this work.The pEGFP-c1 plasmid and pEGFP-c1-pprI gene recombinant plasmid were transferred into anterolateral muscle of mice with in vivo electroporation technology.The mice were irradiated by 6 Gy 60Co γ-rays in whole body and the mortality of mice was observed within 30 days after irradiation.In addition,the mouse were irradiated with 4 Gy γ-rays and then the peripheral blood cell number,apoptosis rates of thymocyte cells,spleen cells and bone marrow cells were observed in the days of 1,7,14,28 and 35 after irradiation while the histopathological changes of lung and testis were observed in the days 7 and 28 after γ-ray irradiation.Results The highest gene transfection efficiency of muscle cells was obtained in a Plasmid injection amount of 50 μg/50 μl and electric field strength of 200 V/cm.The acute radiation mortality of pEGFP-c1-pprI gene recombinant plasmid transfer group was 30％,lower than that of irradiation group (60.0％) and pEGFP-c1 plasmid transfer group (63.3％) after 6 Gy γ-ray irradiation (x2 =4.90,6.24,P ＜ 0.05).Compared with the irradiation group and pEGFP-c1 plasmid transfer group,the WBC count of pEGFP-c1-pprI gene recombinant plasmid group in peripheral blood of mice was significantly higher in the days of 1,7,14 and 28 (F =16.26,8.10,6.37,10.74,P ＜0.05),PLT count was significantly higher in days of 7 and 14 (F =7.36,5.71,P ＜ 0.05),meanwhile the lymphocyte percentage was increased significantly on the 7th day (F =18.43,P ＜ 0.05) after irradiation.On the other hand,the apoptosis rates of thymocyte cells and bone marrow cells were significantly decreased in the days of 1,7,14,28 and 35 (F =3.88,14.91,14.14,39.86,5.65,P ＜0.05 and F=53.70,11.75,21.78,41.40,4.54,P ＜0.05) while the apoptosis rate of spleen cells was significantly decreased in the days of 1,7,14 and 28 (F =97.95,56.61,33.55,14.71,P ＜0.05) after irradiation.Finally,the radiation histopathological changes of lung and testis of the pEGFP-c1-pprI gene recombinant plasmid group were slight and easy to recover.Conclusions Transfection of pprI gene of Deinococcus radiodurans by in vivo electroporation has significant protective effect on the acute radiation injury in BALB/c mice,which may have important clinical applications.
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Objective To construct the eukaryotic expression vector of pprI gene from Deinococcus radiodurans R1 and investigate its radioresistant effects in eukaryotic cells.Methods A recombinant vector pEGFP-c1-pprI was constructed by DNA recombinant technique.The empty vector pEGFP-c1 and the pEGFP-c1-pprI were transferred into human lung epithelial cells Beas-2B by LipofectamineTM 2000,respectively.Then the infected cells were screened in order to develop a cell line with stable expression of pprI gene.Cell survival rate was tested by clone-forming assay.Cell cycle distribution and apoptosis were detected by a flow cytometry.The fluorescence intensity of reactive oxygen species (ROS) was observed by a fluorescent microscope.γ-H2AX foci in the irradiated cell was detected by immunofluorescence.Results The eukaryotic expression plasmid of pprI prokaryotic gene was constructed and PprI fusion protein was expressed in human lung epithelial cells successfully,and the cell line (2BG) with a stable pprI gene expression was established.After irradiation,the cell survival fraction of 2BG cells was significantly higher than Beas-2B cells so that the value of D0 、Dq and N of the survival curve were increased.Moreover,the fluorescence intensity of ROS and the number of γ-H2AX foci in 2BG cells were also lower than those of B eas-2B cells(F =16.73,19.47,6.94,P ＜ 0.05).Between these two cell lines,the apoptosis rate and cell cycle G2 arrest also had significant difference (F =139.73,237.92,P ＜ 0.05).Conclusions The pprI gene from Deinococcus radiodurans RI can be stably expressed in the eukaryotic cells and it allows the transferred cells to have a radioresistant function.
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BACKGROUND: Effective treatment for severed acute radiation sickness (over 8 Gy) has not been obtained at present. Mesenchymal stem cells, which are shown to secrete hematopoietic cytokines and support hematopoietic progenitors, play an important role in cute radiation sickness. OBJECTIVE: To investigate the therapeutic potential of non-adherent bone marrow-derived stem cells in the treatment of acute radiation injury induced by 8.5 Gy X-ray irradiation, as wel as the mechanisms involved. METHODS: Non-adherent marrow-derived stem cells from the long bone of fetal limbs were col ected for analyzing surface antigens, cel cycle, osteogenic and adipogenic differentiation potential, and expressions of vascular endothelial growth factors and Annexin A2. After being exposed to 8.5 Gy total body irradiation, BALB/C mice were randomly assigned into transplantation group and control group. Mice in the transplantation group were given 3×106 CFDA-SE labeled human non-adherent bone marrow-derived stem cells, and those in the control group were given 0.3 mL normal saline. Then, the survival rate, peripheral white blood cells at different time, pathologic change and angiogenesis of the bone marrow were observed. RESULTS AND CONCLUSION: After X-ray irradiation, transplanted non-adherent mesenchymal stem cells appeared to have a homing to the site of injury. The survival rate of mice in the transplantation group was much higher than that in the control group. Compared with the control group, the white blood cells in the transplantation group decreased more slowly while recovered more rapid: the nadir appeared at day 14 after transplantation while it recovered within 30 days. The bone marrow of mice in the transplantation group regenerated more actively and had more hematopoietic islands than those in the control group on day 21. In addition, bone marrow angiogenesis of the transplantation group was more obvious than that of the control group. In conclusion, human fetal non-adherent bone marrow-derived stem cells could promote bone marrow angiogenesis in a mouse model of acute radiation injury, through which they could play an important role in tissue regeneration of acute radiation injury.
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PURPOSE: To investigate ultrastructural changes of the mouse lung induced by whole lung gamma irradiation and to evaluate the effect of prophylactic administration of steroid against acute lung injury. MATERIALS AND METHODS: One hundred and twenty ICR mice were used and whole lung was irradiated with telecobalt machine. Whole lung doses were 8 and 12Gy, and 10mg of methyl prednisolone was administrated intraperitoneally for two and four weeks. At the end of the observation period, mice were sacrificed by cervical dislocation. The lungs were removed and fixed inflated. Histopathological examination of acute radiation injuries were performed by light microscopic and transmission electron microscopic examination. RESULTS: Control group with 8Gy is characterized by damage to the type I pneumocyte and the endothelial cell of the capillary, edema of alveolar wall and interstitium, and fibroblast proliferation. Control group with 12Gy is characterized by more severe degree of type I pneumocyte damage and more prominant inflammatory cell infiltration. Destructed cell debris within the alveolar space were also noted. After steroid administration, 8Gy experimental group showed decreased degree of inflammatory reactions but fibroblast proliferation and basal lamina damages were unchanged. Experimental group with 12Gy showed lesser degree of inflammatory reactions similar to changes of 8Gy experimental group. CONCLUSION: These studies suggest that the degree of interstitial edema and inflammatory changes were related to radiation dose but proliferation of the fibroblast and structural changes of basal lamina were not related to radiat- ion dose. Experimental administration of steroid for 2 to 4 weeks after whole lung irradiation suggest that steroid can suppress alveolar and endot- helial damages induced by whole lung irradiation but proliferation of the fibroblast and structural changes of basal lamina were not related to administration of steroid.