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.

Correlation between overexpression of PC4 in lung adenocarcinoma with lymph node metastasis / 重庆医学

Objective To investigate the promotion effect of human transcriptional positive cofactor 4 (PC4) overexpression on lymphatic metastasis in lung adenocarcinoma .Methods 96 samples of lung adenocarcinoma tissue were collected .The immuno‐histochemistry(IHC) and real‐time quantitative polymerase chain reaction (qRT‐PCR) were adopted for detecting the expression levels of PC4 protein and mRNA .The correlation of PC4 expression with lymphatic metastasis and TNM stage was analyzed .Re‐sults The expression of PC4 protein was positively correlated mRNA in lung adenocarcinoma (r=0 .63 ,P<0 .01);the expression of PC4 protein was positively correlated with lymph node metastasis (χ2 =8 .29 ,P<0 .01) and TNM stage (χ2 =4 .71 ,P<0 .05);the expression of PC4 mRNA was also positively correlated with lymph node metastasis (χ2 = 8 .40 ,P< 0 .01) and TNM stage (χ2 =5 .10 ,P<0 .05) .Conclusion PC4 overexpression is found to be closely associated with the lymph node metastasis and TNM stage .PC4 may facilitate the lymph node metastasis of lung adenocarcinoma .

Study on non-enzymatic separation and culture method of adipose-derived stem cells / 重庆医学

Objective To explore a separation and culture method of human adipose-derived stem cells(ADSCs) suitable for the clinical application .Methods The non-enzymatic method and the collagenase digestion method were adopted to isolate and culture the cells from the human adipose tissue in the individuals with liposuction .The characteristics of isolated mesenchymal stem cells were comparatively analyzed .Results The required time in the non-enzymatic method was one third of that in the collagenase di-gestion method and the cellular morphology ,reproductive capacity ,immunophenotype and differentiation potential of the isolated cells were consistent to those isolated by the collagenase digestion method .Conclusion The no-enzymatic method may isolate and culture ADSCs from the adipose tissue in the individual with liposuction ,which is a safety and reliable isolation and culture method of human adipose tissue-derived stem cells suitable for clinical application .

Enhancement of distribution of dermal multipotent stem cells to bone marrow in rats of total body irradiation by platelet-derived growth factor-AA treatment / 中华放射医学与防护杂志

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.

Effects of dermal multipotent cell transplantation on skin wound healing.

There is increasing evidence that dermis contains adult multipotent stem cells. To investigate the effects of dermis-derived multipotent cells on wound healing, we transplanted a clonal population of dermis-derived multipotent cells (termed as DMCs) by topical and systemic application into the skin wound of rats with simple wounds and rats with combined wound and radiation injury. Our results suggest that both topical and systemic transplantation of DMCs accelerate the healing process in rats with a simple wound; the promoting effect by topical transplantation occurs earlier than systemic transplantation. However, systemic transplantation of DMCs promotes the healing process in irradiated rats, while topical transplantation of DMCs fails. Further studies on the mechanisms of DMCs to promote wound healing indicate that the supernatant of DMCs could promote the proliferation of fibroblasts and epidermal cells; DMCs expressed transcripts of a series of cytokines and extracellular matrix molecules, including VEGF, PDGF, HGF, TGF-beta, ICAM-1, VCAM-1, and Fibronectin, which were closely related to the wound healing by DNA microarray analysis. The implanted DMCs can engraft into recipient skin wounded tissues after transplantation by the FISH analysis with Y-chromosome-specific probe. Systemic transplantation of DMCs also promotes the recovery of peripheral white blood cells in irradiated rats. These results demonstrate the different effects of DMCs on wound healing in non-irradiated and irradiated rats and illustrate the importance of optimizing wound healing via the topical or systemic transplantation of stem cells.

Skin: a promising reservoir for adult stem cell populations.

Plasticity of adult cells has been identified in several post-natal tissues in the past few years and has attracted special attention in regenerative medicine. Skin is the biggest organ in the body. Adult skin consists of epidermis, dermis and appendages such as hairs and glands which are linked to the epidermis but project deep into the dermal layer. Skin stem cell biology has been a focus of increasing interest in current life science. Committed stem cells with limited differentiation potential for regeneration and repair of epidermis have been known for decades. Recent studies further report that adult skin tissues contain cell populations with pluripotent characteristics. Multipotent stem cells from hair follicle and non-follicular skin, both in epidermal and dermal tissues, are found to have the differentiation capacity to generate multiple cell lineages. Basing on the present data, our hypothesis is that skin may serve as a local reservoir of various adult stem cell populations, including committed stem cell populations and pluripotent stem cell populations both in epidermal and dermal tissues. Given its easy accessibility, stem cells in skin will not only provide an experimental model for skin biology, but also may provide an experimental model for studying the epithelial-mesenchymal interactions of several other organs outside of skin. The stem cell populations in skin tissues may also have extensive therapeutic implications in the replacement of skin and may serve as an alternative source of stem cells for several other organs outside of skin. The in situ activation and mobilization of stem cell populations in the skin is an ideal way to renew and repair epidermis and dermis, even appendages.

Long-term culture of dermis-derived multipotent stem cells and the effects of collagen sponge on their growth in vitro / 生物医学工程学杂志

Autologous multipotent stem cells are most relevant cells for regenerative medicine and show prosperous future in the treatment of human diseases. Previous reports have indicated that multipotent stem cells (MSCs) can be obtained from bone marrow and adipose tissues. In this study, we proved that dermis may be another source of these cells. MSCs were isolated from the dermis of newborn rats one day old by adhesion competition and successive culture. These cells conserved the ability to differentiate to osteoblasts, chondrocytes and adipocytes by induction media containing dexamethasone. After long term of more than 6 months, till 25th generation, the cells still maintained the characteristics of stem cells: high activity of self-renewal and multipotency. Mixed collagen matrix from dermis could promote the growth of dermis-derived multipotent stem cells and collagen sponge stent could promote their three-dimensional growth in vitro.

Effects of matrix metalloproteinase 3 on wound healing: an experimental study / 解放军医学杂志

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.

Prospects of Research on Bone Marrow Mesenchymal Stem Cells / 中国实验血液学杂志

Besides hematopoietic stem cells, bone marrow also contains another type of stem cells called mesenchymal stem cells (MSCs). With different induced conditions, MSCs have the ability to differentiate into a variety of nonhematopoietic tissue cells, including osteoblasts, chondroblast, adipocytes, myoblasts, astrocytes, and so on. MSCs can be readily obtained from bone marrow by their adhesion to plastic and expansion in culture. Also they can be genetically engineered by transduced target genes. MSCs may be the farget cells for both cell therapy and gene therapy for diseases derived from many different nonhematopoietic tissues.

Spontaneous malignant transformation of dermis-derived adult multipotential stem cells in vitro / 第三军医大学学报

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.