BACKGROUND:Skin transplantation is regarded as the most effective therapy for large-area skin defects, which is limited by donor sources and immune rejection. Therefore, it is extremely accelerate the construction of the dermis in skin tissue engineering.
OBJECTIVE:To investigate the effects of bone marrow mesenchymal stem cels/calcium alginate gel, basic fibroblast growth factor and degradation membrane on the repair of ful-thickness skin defects.
METHODS:Bone marrow mesenchymal stem cels were isolated from 15 New Zealand rabbits, and then cultured, amplified, subcultured and purified. Three ful-thickness skin defects were made on the back of every rabbit, and randomly treated with bone marrow mesenchymal stem cels/calcium alginate gel, basic fibroblast growth factor and degradation membrane as experimental group, bone marrow mesenchymal stem cels/calcium alginate gel as control 1 group, and calcium alginate gel as control 2 group. The wounds were al covered with amniotic membrane. After 7, 14, 21 days, new wound tissues were taken for hematoxylin-eosin staining, immunohistochemistry staining and image analysis.
RESULTS AND CONCLUSION: Dermis tissues in the experimental group were obviously thicker than those in control 1 and control 2 groups; there were more fibroblasts, vessels and colagen fibers in the experimental group. Especialy at 14 and 21 days after operation, epidermal hyperplasia was faster with a larger coverage area in the experimental group, and at 21 days, the new epidermal tissues mainly exhibited multi-layered structure, which was superior to the control 1 and 2 groups. It folows that the combination of bone marrow mesenchymal stem cels/calcium alginate gel, basic fibroblast growth factor and degradation membrane for skin defects can accelerate the repair and regeneration of the dermis, and thus promote the epidermis regeneration and reconstruction.

BACKGROUNDThe use of stem cells for various clinical applications is highly expected and the production of good quality stem cells is very critical for basic studies. In the bone marrow, hematopoietic and mesenchymal stem cells form a unique niche in which the oxygen tension is low. Hypoxia may have a role in maintaining stem cell fate, self renewal and multi-potency. We investigated whether low oxygen culture would be beneficial for hematopoietic stem cell stemness.METHODSBone marrow cells from 8-10 week aged mice were subjected to hypoxic conditioning by culture for 7days in 20%, 3% and 1% oxygen. For culture,1x105 cell/ml were seeded in colony forming assay in each dish. During the culturing, cell colonies were checked once every three days. Compared to normoxic cells, hypoxic cells weremorphologicallyundifferentiated and counted by Olympus IX71 microscope.RESULTSMore colonies were observed at 3% and 1% oxygen. Statistical significances were identified with granulocytes and macrophage colony (p<0.05) in hypoxic condition.CONCLUSIONSOur data suggests low physiological oxygen culture could improve the stemness of macrophage and granulocytes colony. Long term culture will be necessary to confirm whether low physiological oxygen levels also improve genomic stability.

Background:Mesenchymal stem cells derived from bone marrow and adipose tissue are being applied to tissue engineering and cell therapy. The use of stem cells of various clinical applications is highly expected and the production of good quality stem cells is very critical for basic studies. In the bone marrowmesenchymal stem cells from an unique niche in which the oxygen tension is low. Hypoxia may have a role in maintaining stem cell fate, self renewal and multi-potency. We investigated whether low oxygen culture would be beneficial for mesenchymal stem cell. Results:BMCs from 8-10 week aged, 6 mice were subjected to hypoxic conditioning by culture for 7 days in 20%, 3%, 1% oxygen. For culture 1x106 cell/ml were seeded in media with L-glutamine in each dish. During the culturing, cell colonies were checked once in three days. After cell culture, we stained cells by CD90 then counted CD90 positive cells by fluorescence microscope. More colonies and mesenchymal cells were observed at 3%, 1% oxygen and also colonies were bigger in hypoxic condition. Statistical significances were identified mesenchymal cells (p<0.05) in hypoxic condition. Conclusions:Our data suggests low physiological oxygen culture could improve the differentiation of mesenchymal cells. Long term culture will be necessary to confirm whether low physiological oxygen levels also improve genomic stability.

BACKGROUND: In the recent years, mesenchymal stem cells have become increasingly utilized in regenerative medicine and tissue engineering applications because of their properties for self-renewal, differentiation and immunoregulation. The use of stem cells of various clinical applications is highly expected and the production of good quality stem cells is very critical for basic studies. In the bone marrow, hematopoietic and mesenchymal stem cells from an unique niche in which the oxygen tension is low. Hypoxia may have a role in maintaining stem cell fate, self renewal and multi-potency. We investigated whether low oxygen culture would be beneficial for hematopoietic stem cell and mesenchymalstemcell. MATERIAL: BMCs from 8-12 week aged, 15 mice were subjected to hypoxic conditioning by culture for 8-10 days in 20%, 3%, 1% oxygen. For culture 1x105cell/ml were seeded in colony forming assay and 2x106cell/ml were seeded in L-glutamin mediain chamber slide. We counted cell colonies under different hypoxic condiontins by Olympus IX71 fluorescence microscope. After cell culture in chamber slide, we stained cells by anti-CD90 and anti-CD105 then counted positive cells by Olympus IX71 fluorescence microscope. RESULTS: Compared to normoxic cells and hypoxic cells well morphologically differentiated and counted by Olympus IX71 microscope. More colonies were observed at 3%, 1% oxygen. Statistical significances were identified with granulocytes and macrophage colony (p<0.05) in hypoxic condition. More anti-CD90 and anti-CD105 markers were observed at 3% oxygen condition. Statistical significances were identified in 3% oxygen condition with cell markers(p<0.001). CONCLUSIONS: Our data suggests low physiological oxygen culture could improve the stemness of macrophage and granulocytes colony and improve the differentiation of mesenchymal cells. Long term culturewith additional cell markers will be necessary to confirm whether low physiological oxygen levels also improve genomic stability