ObjectiveTo explore the research progress of the cell sources and related signaling pathways of the wound-induced hair follicle neogenesis (WIHN) in recent years.MethodsThe literature related to WIHN in recent years was reviewed, and the cell sources and molecular mechanism were summarized and discussed.ResultsCurrent research shows that WIHN is a rare regeneration phenomenon in the skin of adult mammals, with multiple cell origins, both hair follicle stem cells and epithelial stem cells around the wound. Its molecular mechanism is complicated, which is regulated by many signaling pathways. Besides, the process is closely related to the immune response, the immunocytes and their related cytokines provide suitable conditions for this process.ConclusionThere are still many unsolved problems on the cellular origins and molecular mechanisms of the WIHN. Further study on the mechanisms will enhance the understanding of adult mammals’ hair follicle regeneration and may provide new strategy for functional healing of the human skin.
Objective To investigate the effect of repeated freezing and thawing combining nuclease treatment on the decellularization of bovine tendons, and the morphology, structure, biochemical compositions, and mechanical properties of the decellularized tendons. Methods A total of 48 fresh 1-day-old bovine Achilles tendons were randomly divided into 3 groups (n=16): fresh normal tendons (group A), repeated freezing and thawing for 5 times (liquid nitrogen refrigeration/37℃ thawing, group B), and repeated freezing and thawing combining nuclease processing for 24 hours (group C). In each group, 2 tendons were used for scanning electron microscope (SEM), 3 tendons for histological and immunohistochemical observations, 3 tendons for DNA content detection, and 8 tendons for biomechanical testing. Results SEM observation indicated the intact, aligned, and densely packed collagen fibers with no disruption in groups A and B, and the slightly loose collagen fibers with little disruption in group C. The alcian blue staining, sirius red staining, and immunohistochemical staining showed that the most of glycosaminoglycan, collagen type I, collagen type III, and fibronectin in group C were retained after decellularization treatment. HE and DAPI staining showed that the cell nuclei between the collagen fibers were clearly visible in groups A and B; however, the cell nuclei between collagen fibers almost were invisible with a few residual nuclei on the endotendineum in group C. DNA quantitative detection confirmed that DNA content in group C [(0.05 ± 0.02) μg/mg] was significantly lower than those in group A [(0.24 ± 0.12) μg/mg] and group B [(0.16 ± 0.07) μg/mg] (P lt; 0.05). Biomechanical testing showed that the values of tensile strength, failure strain, stiffness, and elastic modulus were different among 3 groups, but no significant difference was found (P gt; 0.05). Conclusion Repeated freezing and thawing combining nuclease processing can effectively remove the component of cells, and simultaneously retain the original collagen fibrous structure, morphology, most of the extracellular matrix compositions, and mechanical properties of the bovine tendons.
Objective To evaluate the tensile mechanical characteristics of decalcified cortical bone matrix with different thicknesses so as to provide an experimental basis for the scaffold of tissue engineering. Methods Decalcified cortical bone matrix was prepared from fresh bovine tibia with rapid decalcification techniques. Its physical characteristics including colour, texture, and so on, were observed. Then the decalcified rate was calculated. Decalcified cortical bone matrices were radially cut into sl ices with different thicknesses along longitudinal axis and divided into 4 groups: group A (100- 300 μm), group B (300-500 μm), group C (500-700 μm), and group D (700-1 000 μm). Then the sl ice specimens of each group were characterized with tensile test and histological examination. Results General observation showed that decalcified cortical bone matrix with hydrogen peroxide treatment was ivory white with good elasticity and flexibil ity. The decalcified rate was 97.6%. The tensile strength and elastic modulus of groups B, C, and D were significantly higher than those of roup A (P lt; 0.05); there was no significant difference among groups B, C, and D (P gt; 0.05). The stiffness in 4 groups increased gradually with the increasing thickness, it was significantly lower in group A than those in groups B, C, and D (P lt; 0.05), and in groups B and C than that in group D (P lt; 0.05). While there was no significant difference in ultimate strain within 4 groups (P gt; 0.05). Histologically, intact osteon was observed in every group, with an average maximum diameter of 182 μm (range, 102- 325 μm). Conclusion The mechanical properties of decalcified cortical bone matrix might depend on the integrity of the osteons. Sl ices with thickness of 300 μm or more could maintain similar mechanical properties when decalcified cortical bone matrix is used as a scaffold for tissue engineering.
Objective To review the research progress of the feasibility of a new treatment method for atrophic rhinitis (ATR) based on tissue engineering technology (seed cells, scaffold materials, and growth factors), and provide new ideas for the treatment of ATR. MethodsThe literature related to ATR was extensively reviewed. Focusing on the three aspects of seed cells, scaffold materials, and growth factors, the recent research progress of ATR treatment was reviewed, and the future directions of tissue engineering technology to treat ATR were proposed. Results The pathogenesis and etiology of ATR are still unclear, and the effectiveness of the current treatments are still unsatisfactory. The construction of a cell-scaffold complex with sustained and controlled release of exogenous cytokines is expected to reverse the pathological changes of ATR, promoting the regeneration of normal nasal mucosa and reconstructing the atrophic turbinate. In recent years, the research progress of exosomes, three-dimensional printing, and organoids will promote the development of tissue engineering technology for ATR. ConclusionTissue engineering technology can provide a new treatment method for ATR.