Rats were subjected to 15% body surface area third degree burns combined with 2 , 4 , 6 , and 8 Gy irradiation respectively. 48 hours after injury, the DNA and RNA contents of the bone marrow, lymph nodes, spleen and peripheral blood were found to have marked reduction, which became more marked when the dosage of the radiation was increased. Furthermore, it was found that the DNA content decreased more rapidly than the RNA content and the chnage of RNA was more marked in the hemopoietic tissues than in the peripheral blood. Nucleic acid reduction occurred more severely following 2 Gy irradiation than following 15% BSA third degree burns. After the combined iujury of 8 Gy irradiation and burns, th? reduction of nucleic acids in all the above-mentioned tissues exceeded 50%.The mechanism of the changes of necleic acids in the hemopoietic tissues after combined injury of radiation and burns was discussed. Radiation played a more important role than burns in resulting in the reduction but the synergistic effect of burns could not be neglected and could be clearly demonstrated.

BACKGROUND: Bone marrow mesenchymal stem cells (BMMSCs) can be induced differentiating into osteoblasts and chondroblasts, DNA methylate depressant 5-azacytidine can induce BMMSCs expressing myogenic regulating factors: Myf5 and myopoietin, which involving in the differentiation of BMMSCs into myoblasts.OBJECTIVE: Muscular traumatic fluid containing the highest protein content was screened out and co-cultured with BMMSCs,in order to explore the inductive effect on the proliferation and myogeneis of BMMSCs.DESIGN : Standardized comparative study.SETTING .:At State Key Laboratory of Trauma, Bums and Combined Injury,Institute of Combined Injury, Medical College of Preventive Medicine, Third Military Medical University of Chinese PLA.MATERIALS: Muscular traumatic model was established on 18 Balb/C pure rats for the extraction of muscular traumatic fluid, the inductive effect of the fluid on BMMSC was then compared with 5-azacytidine.METHODS:This study was carried out at State Key Laboratory of Trauma,Burns and Combined Injury, Institute of Combined Injury, College of Preventive Medicine, Third Military Medical University of Chinese PLA from April 2001 and September 2003. Bradford colorimetric was used to detect the protein content in the muscular traumatic fluid, and the fluid with the highest protein was used to co-culture with BMMSC, whose effect on the proliferation of BMMSC was measured with MTT methods at day 0, 3, 6, 9, 12, 15.RT-PCR technique was used to detect the expression of myopoietin at day 6,with its myogenic effect compared with that of 5-azacytidine.fluid on BMMSC.eration of BMMSC: the proloferative activity of BMMSC in traumatic fluid genic effect of traumatic fluid on BMMSC: myopoietin could not be found expressed in traumatic fluid group, but strongly expressed in 5-azacytidine group.CONCLUSION: Muscular traumatic fluid can promote the proliferation of BMMSC, but has no myogenic effect.

Objective To obtain skin seed cells which can highly express active vascular endothelial growth factor 165(VEGF165) so as to promote refractory wound healing by gene therapy in combination with cell engineering.Methods After pIRES2-EGFP-hVEGF165 was transfected into dermal mesenchymal stem cells(DMSCs) by lipofectin,the expression of VEGF mRNA was detected by RT-PCR,VEGF protein in the supernatant and in the cells were assayed by enzyme-linked immunosorbent assay(ELISA) and Westen blotting respectively.To evaluate the activity of VEGF secreted by transfected DMSCs,hECV304 was cultured with the supernatant of transfected DMSCs and its proliferation activity was analyzed by MTT assays.Meanwhile,the proliferation activity of VEGF-transfected DMSCs and non transfected DMSCs was investigated by MTT.Results The results of RT-PCR,ELISA and Western blot demonstrated that the expression of VEGF in transfected DMSCs was about 1.6 times than that of control DMSCs.The product not only enhanced the proliferation of hECV304 but also increased the proliferation of transfected DMSCs.Conclusion The plasmid pIRES2-EGFP-hVEGF165 is successfully transfected into DMSCs with the aid of lipotransfection,and hVEGF165-transfected DMSCs might high-efficiently secrete highly active VEGF165.

Objective To explore the protective effect of atorvastatin on irradiated endothelium and the thrombomodulin(TM)expression.Methods Cultured human coronary artery endothelial cells(HCAEC)and human umbilical vein endothelial cells(HUVEC)were treated by atorvastatin at the final concentration of 10 μmol/ml for 10 min,and then irradiated with 2 and 25 Gy.Cell cycles status and TM expression were quantitatively measured by flow cytometry 24 hours after irradiation.Protein C activation in endothelial cells was also assessod.Results After administration with atorvastatin for 24 h,the TM expression increased by 77%,59% and 61% in normal control group,2 Gy group and 25 Gy group,respectively(t=27.395,26.420,58.065;P=0.000).The protein C levels decreased by 23% and 34% compared with the normal group post-irradiation to 2 and 25 Gy,but increased by 79% and 76% compared with the irradiated control group after administration with atorvastatin.The rates of cell apoptosis decreased by 6% and 16% in 2 Gy and 25 Gy groups,respectively after administration with atorvastatin for 24 h(t=4.178,17.863;P=0.000).Conclusions Atorva statin can protect endothelia cell from irradiation-induced apeptosis by increasing TM expression and protein C activation.

Objective To clone platelet-derived growth factor A chain (PDGF-A) gene and insert PDGF-A gene into. Enhanced green fluorescent protein (EGFP) vector and then transformed into dermis-drived mesenchymal stem cells (DMSCs). Methods cDNA clones encoding human PDGF-A gene were isolated from a human hepatoma cell line mRNA by reverse transcription-polymerase chain reaction (RT-PCR). The PCR amplified fragment of PDGF-A gene was cloned into pMD18-T vector. The eukaryotic expression vector pEGFP-N1/PDGF-A was constructed by subcolone PDGF-A gene into pEGFP-N1 vector. PDGF-A gene was transfected into DMSCs with the help of Fugene 6 transfection reagent. Results Full cDNA sequence encoding human PDGF-A gene had been cloned, which sequence was consistent with the reported sequence in GenBank by sequence assaying. Conclusion cDNA sequence encoding human PDGF-A gene was successfully cloned into pEGFP-N1. The transient expression of PDGF-A gene in DMSCs has been realized.

Objective To observe whether dermal multipotent stem cells (dMSCs) treated with platelet-derived growth factor-AA ( PDGF-AA )could distribute more frequently to the bone marrow in rats of total body irradiation (TBI).Methods Male dMSCs were isolated and 10 μg/L PDGF-AA was added to the culture medium and further cultured for 2 h.Then the expression of tenascin-C were examined by Western blot, and the migration ability of dMSCs was assessed in transwell chamber.The pre-treated dMSCs were transplanted by tail vein injection into female rats administered with total body irradiation, and 2 weeks after transplantation, real-time PCR was employed to measure the amount of dMSCs in bone marrow.Non-treated dMSCs served as control.Results PDGF-AA treatment increased the expression of tenascin-C in dMSCs, made (1.79 ± 0.13) × 105 cells migrate to the lower chamber under the effect of bone marrow extract, and distributed to bone marrow in TBI rats, significantly more than ( 1.24 ± 0.09) ×105 in non-treated dMSCs (t = 8.833, P ＜ 0.0l ).Conclusions PDGF-AA treatment could enhance the migration ability of dMSCs and increase the amount of dMSCs in bone marrow of TBI rats after transplantation.

Objective　To compare the irradiation-protective and inter-synergestic effects of E838,WR-2721, Rubia cordifolia, cystamin e hydrochloride and ethinyl estradiol on radiation and combined radiation-burn injury. Methods　Above-mentioned drugs were given to the mice i ntraperitoneally, or intragastrcally, then, the mortality and the average surviv al d for 30 d were observed before and after the administration of the drug s. Results　①When drugs were before injury , the survival rate and the average survival d of the radiation and combined radiation-burn injured mice were increased obviously with the best effect in E838 and WR-2721. ②When drugs were given after injury, E838 and R. cordifolia also kept the effect. ③Combined appling WR-2721（pre) and E838（post）displayed a significant syner gistic reaction. Conclusion　E838 and WR-2721 are more e ffective than the others in the prevention of radiation.

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.

Objective To explore the feasibility of mobilization circulating MSCs by G-CSF and observe the repairing effect of G-CSF mobilization in severe mouse traumatic brain injury(TBI) model.Methods MSCs-derived bone marrow and peripheral blood(PB) were cultured and its CFU-F were counted after mobilization by G-CSF.At 2,24,48,96,120,144,192,264,336 h after severe TBI in mice was establish,the neurobehavior of mice was measured by neurological examination and motor functional test,and mortality rate and pathologic changes were analyzed.Results MSCs-derived PB were successfully cultured.The CFU-F of mobilization group increased significantly than that of control group(P

Objective To examine the expression of human ?-defensin 2 (hBD_ 2 ) recombinant adenovirus expression vector in rat dermal multipotent stem cells (dMSCs) and to observe the antiseptic activity of recombinant hBD_ 2 . Methods The expression of hBD_ 2 in dMSCs was examined by RT-PR, fluorescent immunochemistry and Western blotting, and the concentration of recombinant hBD_ 2 in supernate was measured by ELISA. The antiseptic activity of recombinant hBD_ 2 was assessed by K-B disc agar diffusion test. Results hBD_ 2 could be effectively expressed in dMSCs, and the concentration of recombinant hBD_ 2 in supernate was about 743.6 ng/ml . Recombinant hBD_ 2 in supernate showed antiseptic activity. Conclusion Recombinant adenovirus expression vector of hBD_ 2 could be effectively expressed in dMSCs, and the recombinant hBD_ 2 in supernate showed obvious antiseptic effects toward some standard bacteria lines.