Application of information-based teaching in the experimental teaching of nuclear protection medicine / 中华医学教育探索杂志

Information-based teaching was applied in the experimental teaching of nuclear protection medicine based on its own features.The teaching content was sent to students as micro-video via an information platform before class for preview;during the class,the teaching was performed in the form of lectures by students and experiments in groups;after class,students were required to submit reports of experimental improvement or innovative experimental design.A comprehensive assessment was performed for preview,classroom operation,question answering in class,and experimental reports.The results of teaching practice showed that this teaching mode can effectively stimulate the students' interests in learning,enhance their research and innovation abilities,and improve the experimental teaching effect of nuclear protection medicine.

Enhanced autophagy protects hepatic cells from radiation injury / 中华放射医学与防护杂志

Objective To study the influence of radiation on autophagy and its protective effect on radiation injury of hepatic cells.Methods Autophagy in mouse liver tissues was examined by GFP-LC3 staining and Western blot.Radiation-induced hepatic injury was evaluated by ALT and AST in mouse serum,protein expressions,and H & E and TUNEL staining of liver tissue.L02 cells were used for in vitro study.Chloroquine and rapamycin were used to manipulate the level of autophagy.Results Total body irradiation (TBI) of 8 Gy caused an increase of autophagy in mouse liver tissue and AST level in serum (t =-7.47,P ＜0.05) at 12 h after irradiation.Irradiation significantly increased the apoptotic level in liver tissue as well.Inhibition of autophagy by chloroquine caused a further increases of AST [IR:(345.42±35.25)U/L vs.IR +CQ:(433.42 ±40.07)U/L,t =-2.86,P＜0.05] and ALT [IR:(35.67 ± 8.08) U/L vs.IR+CQ:(98.5±26.67)U/L,t=-3.09,P＜0.05] in the serum,and it also promoted apoptosis in live tissue.However,rapamycin as an autophagy promoter showed protective effect for radiation-induced hepatic injury [AST:IR:(345.42 ± 35.25) U/L vs.IR + Rap:(278.42 ± 20.09)U/L,t =-2.86,P ＜ 0.05].Similar changes of autophagy and apoptosis in L02 cells were also observed in the cells treated with chloroquine and rapamycin.Inhibition of autophagy by CQ caused an increase of ROS in vitro and in vivo and further increased ALT and AST levels in serum,reduced L02 cell viability.Activation of autophagy by Rap effectively reversed those changes.Conclusions Autophagy protects hepatic cells from radiation injury by decreasing ROS induction,which provides a potential target for the development of new clinical regimens against radiation induced liver injury.

Engraftment of bone marrow-derived cells after nonlethal radiation in syngeneic C57BL/6 mice / 中华放射医学与防护杂志

Objective To study the characteristics of cell engraftment in mice at a lower dose under nonlethal radiated condition.Methods A syngeneic C57BL/6 mouse model,transplanted with 1 × 107 bone marrow cells and exposed to 2.5 Gy whole body irradiation (WBI),was selected to study the chimerism of cells from green fluorescent protein positive (GFP +) transgenic mice.The control group was injected with GFP + cells without receiving irradiation.In addition,an allogenic transplantation model of BALB/c mice was also investigated which was infused by GFP + cells from C57BL/6 mice.The engraftment of bone marrow-derived cells (BMDCs) was detected by immunohistochemistry in bone marrow,liver,lung,small intestine and spleen.Results The transplanted bone marrow cells successfully grafted in the haematopoietic tissues from syngeneic GFP transgenic mice.The transplanted GFP+ cells were also detected in the non-haematopoietic tissues,such as the small intestine,liver,spleen and lung,after irradiation.However,a lethal dose irradiation of 8 Gy was required to establish successful chimerism in allogeneic transplantation model by infusing the bone marrow cells from C57BL/6 mice to BALB/c mice.Conclusions Bone marrow-derived cells can be successfully grafted into various recipient tissues receiving a 2.5 Gy dose of radiation in syngeneic mice,but not in allogeneic mice.This nonlethal model may help to further study the plasticity and mechanism of bone marrow-derived cells in tissue repair and regeneration after radiation injury.

Transdifferentiation of allotype BMSCs into hepatocytes in bone marrow chimeric mice / 第三军医大学学报

Objective To detect whether mice bone marrow mesenchymal stem cells(BMSCs)can contribute to the regeneration of hepatocytes in bone marrow chimeric mice.Methods Female recipient mice(C57BL/6J)underwent whole body gamma-ray irradiation with a dose of 10 Gy to ablate their bone marrow,followed by immediate tail vein injection of BMSCs isolated from male GFP transgenic mice.Animals were killed at different phase points:1 week,1 month,and 3 months.Using fluorescence microscope we directly observed GFP-positive cells in the liver frozen sections,and we also prepared the parafilm sections to detect the GFP-positive cells and the coexpression of GFP and Alb,CK18 by immunohistochemistry and immunofluorescence respectively.Results We found numerous GFP-positive cells in recipient mice liver at 1 week after BMSCs transplantation,some at 1 month and seldom at 3 months.There were some cells coexpressing GFP and Alb,CK18 at all the phase points.Conclusion Allotype BMSCs can differentiate into Alb and CK18 positive hepatocytes in bone marrow chimeric mice,which will become an ideal cell resource for liver tissue project.

Construction and identification of recombinant adenovirus expressing hPDGF-A and hBD-2 / 第三军医大学学报

Objective To further determine their possible synergistic effect on accelerating wound healing, adenovirus vector containing recombinant human hPDGF-A and hBD2 genes was constructed and the expression of exogenous genes in transformed mesenchymal stem cells derived from rat bone marrow was observed. Methods By putting IRES in the middle of hPDGF-A and hBD2, these two genes were expected to be expressed individually. The shuttle vector was named as pAdTrack-hPDGF-A-IRES2-hBD2, which homologously recombinated with Adeasy-1 in BJ5183 cells and formed the mammalian expression vector pAdeasy-hPDGF-A-IRES2-hBD2. Furthermore, the recombinant vector was packaged in 293 cells into infectious recombinant adenovirus, which were used to infect BMSCs. The expression of hPDGF-A and hBD2 in BMSCs was detected by RT-PCR. Results We successfully constructed recombinant adenovirus vector that simultaneously expressed hPDGF-A and hBD2. The expressions of hPDGF-A and hBD2 were confirmed by RT-PCR on transformed BMSCs. Conclusion The established BMSCs that overexpressed hPDGF-A and hBD2 provide a new strategy of combining cell therapy and gene therapy to promote wound healing, especially the chronic one.