Objective To explore the changes and significance of matrix metalloproteinase 3 (MMP3) during wound healing in rat. Methods Wound fluids and dermal pluripotent stem cells (DPSCs) were isolated with routine method from rats, and they were purified and expanded. Wound fluid was collected on the first day to serve as wound microenvironment, then the responses of DPSCs to wound fluids were investigated, and the expression of MMP3 protein in DPSCs was determined by immunohistochemistry staining. Meanwhile, animal models were repruduced with cutaneous incision and suturing, and the animals were respectively assigned to intractable wound group, in which rats received whole body irradiation, and simple wound group, in which no irradiation was given. The rats were sacrificed on 3rd, 5th, 7th, 10th and 14th day posttrauma (n=5 each), and specimens of wound tissue were harvested, fixed with 10% formalin solution. Twenty four hours later, the samples were dehydrated and embeded, then paraffin section were made. Paraffin sections were stained with hematoxylin and eosin (HE) staining. Light microscopy was used to observe the pathological changes in wounds. Five randomly selected fields were observed under a ?40 objective to evaluate the histological features, especially the amount of tissue repairing cells in wounds. Furthermore, MMP3 contents in wound sites were determined by immunohistochemistry assay and image analysis. Results The expression of MMP3 in DPSCs increased significantly after stimulation by wound fluids. MMP3 contents in rats of simple wound group increased significantly, especially in the dermal tissues, and the peak value appeared 5-7 days after trauma. MMP3 contents in rats of intractable wound group were significantly less than those of simple wound group, and the time when the peak value appeared was also delayed till the 10th day after trauma. Conclusions MMP3 may be an important substrate involved in wound healing. DPSCs may participate in the processes of wound repairing via high expression of MMP3.

One hundred and ninety-one rats were injured with blast super-pressure and 64 out of the 191 died within 30 minutes after injury.The characteristics of the myocardial damages of the rats were as follows:(1)Disturbance of myocardial circulation;(2)Air embolism and interstitial emphysema;(3)Degeneration and necrosis of the myocardium; severance of myocardial fibers ;and separation of intercalated discs.It was speculated that the causes of these myocardial pathological changes are the direct damage of blast superpressure and the secondary effects of pulmonary damages.Protection of the heart and the lungs from blast super-pressure injury is the key to reduce the number of immediate death in blast injury.

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 study the phenomena and the related mechanisms of malignant transformation of dermis derived multipotential stem cells in vitro . Methods Clonal populations of dermal multipotential stem cells were passaged sequentially in vitro , and the subcutaneous inoculation of cells in nude mice was used for observation of the tumor formation. The transcript profiles of the transformed cells were analyzed by DNA microarray technique. Results Dermal multipotential stem cells underwent spontaneous malignant transformation after serial subculture in vitro . Cells grew out of control, and chromosome number was abnormal. After cells were inoculated subcutaneously into BALB/c nu/nu athymic mice, tumors characterized by fibrous histiocytoma were produced. Immunohistochemistry showed that there were different cell populations for the expression of vimentin, cytokeratin, S 100, and ? smooth actin. Detection by DNA microarray technique revealed that the transformed cells expressed multilineage transcripts, indicating that the transformed cells might have the multipotency. Among the differentially expressed genes in transformed cells, most of the up regulated genes were related to the proliferation process, but most of the down regulated genes were growth factors and their receptors. The enhanced expression of the c ki ras gene and its relevant molecules may play important roles in the transformation process. A candidate gene with unknown functions related to the stem cell proliferation was also preliminarily identified. Conclusion Dermal multipotential stem cells can undergo spontaneous malignant transformation in vitro . Further studies of the mechanisms of this process at the molecular level may have significance both in stem cell application and in tumorigenesis.

Objective To find out the best method for elimination of uranium contamination in rat tissues as low as possible by removal of shrapnel fragments. Methods Experimental rats were divided into six groups: route group, decontamination before surgery group, decontamination in incision group, changing surgical appliances group, removing tissues around group, and comprehensive method group. Uranium concentrations in tissues and fluids in all groups were measured at 7, 14, and 21 d after operation. The efficiency of decontamination by different methods was compared. Results The highest uranium concentration in tissues was found in the route group, but the lowest in the comprehensive method group, and the second lowest in removing tissues around group. Conclusion The comprehensive method is the best one in all of the surgical removal methods. The soft tissues around DU shrapnels should be removed if they are not critical organs.

BACKGROUND: As a kind of semitransparent membrane, human amniotic membrance contains many kinds of nutrients, which is a good biological material loaded with keratinocytes.OBJECTIVE: To construct epidermal substitute of the skin from human amniotic membrane loaded with porcine keratinocytes and examine the morphological characteristics of the growth and proliferation of keratinocytes seeded on human amniotic membrane.DESIGN: Single sample study and repetitive measured observation based on the cells.SETTING: Institute of Combined Injuries of Chinese PLA, Academy of Preventive Medicine, Third Military Medical University of Chinese PLA.MATERIALS: The experiment was completed in the State Key Laboratory of Trauma, Burn and Combined Injury and Institute of Combined Injuries of Chinese PLA, Academy of Preventive Medicine, Third Military Medical University of Chinese PLA from January to November 2001. Porcine keratinocytes was collected from Guizhou minipigs aged 3 weeks.METHODS: The primarily cultured keratinocytes of Guizhou minipigs were subcuhured, expanded and bred on the stroma surface of human amniotic membrance at the density of 1.63 × 105/cm2. The growth and proliferation of keratinocytes were observed under inverted microscope every day. From the 3rd day and the 15th day after being cultured, the growth of keratinocytes on human amniotic membrane was examined under light microscope and electron microscope.MAIN OUTCOME MEASURES: The growth of keratinocytes on human amniotic membrane was examined RESULTS: Keratinocytes evidently adhered to the stroma surface of human amniotic membrane about 30 minutes after being cultured, which was observed under inverted microscope. Most keratinocytes grew and adhered to the stroma surface of human amniotic membrane within 24 hours. Monolayer of keratinocytes formed and completely covered human amniotic membrane within 3 days. It was observed under the light microscope that the monolayer of keratinocytes adhered to human amniotic membrane and arrayed tightly. The keratinocytes presented in the shape of polygon, and plasmalemmas of keratinocytes formed many pseudopods under the observation with scanning electron microscope. Keratinocytes adhered to human amniotic membrane well and with many keratinofilaments in them under the observation with transmission electron microscope. Keratinocytes arrayed on human amniotic membrane densely with many cellular debris and some keratinocytes formed cavitations in them due to aging after growth for 15 days under the observation with inverted microscope.CONCLUSION: Human amitotic membrane is a good carrier of keratinocytes cultured on it in vitro, and is able to promote the proliferation of keratinocytes significantly. However, when keratinocytes were loaded on the human amniotic membrane for 15 days, some keratinocytes formed cavitations in them due to aging.

Objectives To investigate the effects of combined radiation and thermal burn injury on the survival of skin allografts and to analyze the relationship between the prolongation of allograft survival and the changes of immune functions of the thymocytes and splenocytes in rats.Methods Wistar rats were irradiated with 3, 4, 5, 6 and 8 Gy of gamma rays. Thirty minutes after radiation, 15% TBSA Ⅲ-degree burn was inflicted to the rats. Twenty-four hours after the burn injury, allografts were used to cover the burn wounds. In the 8 Gy group, 1 hour before skin grafting, the bone marrow cells (4×108) from the same donor were also transplanted. All rats were carefully observed after injury. The rats with single radiation injury of 5 Gy gamma rays, with single burn injury and with combined radiation-burn injury were killed 3, 7, 10, 15 and 30 days after skin grafting for immunological assay and pathological study.Results All the allografts in the single burn group were rejected in 10 days. In the combined injury groups, the survival rates of the allografts in rats undergoing 3 and 4 Gy radiation were 20% and 30%, respectively. In the combined injury groups undergoing 5, 6 and 8 Gy radiation, the 10-day survival rates of the allografts were 69%, 88% and 100% respectively, and the 30-day survival rates in the three groups were 36%, 42% and 100% separately. The grafted allogenic skin, with normal epithelial cells and good vascularity, healed well with the recipient's skin. Hairs grew well from the allografts 30 days after grafting. Three, 7 and 15 days after allografting, in the single burn group, the proliferative activities of the thymocytes were 90%, 185% and 130% of the preinjury level, and the antibody forming capacities of the splenocytes were 200%, 171% and 300% of the preinjury level, respectively; in the combined injury groups, the proliferative activities were 6%, 99% and 91% of the preinjury level, and the forming capacities were 2%, 36% and 90% of the preinjury level.Conclusions The survival rate of allograft in rats undergoing combined radiation and thermal burn injury rises with the increase in radiation dosage. The allograft covering single bun injury is severely rejected by immune reaction. The prolongation of the survival of allograft in combined injury group mainly results from radiation that suppresses immune functions.