Bibliothek

Notizen: Fetal cutaneous wounds that occur in early gestation heal without scar formation. Although much work has been done to characterize the role of transforming growth factor-β (TGF-β) isoforms and their receptors in the wound healing process, their roles in scarless wound repair observed in early gestation and their functions in human fetal skin development, and structural and functional maintenance are still not well understood. In this study, we explore the expression and distribution characteristics of three TGF-β isoforms and their receptors, TGF-βRI (TBRI) and TGF-βRII (TBRII), in fetal and postnatal skins to understand the relevance of these five proteins to skin development and elucidate the mechanism(s) underlying the phenotypic transition from scarless to scar-forming healing observed during fetal gestation. Fetal skin biopsies of human embryo were obtained from spontaneous abortions at different gestational ages from 13 to 32 weeks and postnatal skin specimens were collected from patients undergoing plastic surgery. Gene expression and positive immunohistochemical signals of TGF-β1, TGF-β2, TGF-β3, TBRI, and TBRII could all be detected in fetal and postnatal skins. In early gestation, gene expression of TGF-β1, TBRI, and TBRII was weaker and protein contents were less compared with postnatal skins (p 〈 0.05). In contrast, more TGF-β2 mRNA transcript was found in early gestation than in late gestation and in postnatal skins, whereas protein content of this growth factor increased during gestation. Lastly, mRNA transcript and protein contents of TGF-β3 were apparently higher in early gestation compared to postnatal skin (p 〈 0.05). In postnatal skin, granules containing the three TGF-β isoforms were mainly distributed in the cytoplasm and extracellular matrix of epidermal cells, interfollicular keratinocytes, and some fibroblasts. TBRI and TBRII were chiefly located in the cellular membrane of epidermal keratinocytes and some fibroblasts. The endogenous three TGF-β isoforms and their receptors may be involved in the development of embryonic skin and in the maintenance of cutaneous structure and function, and also in postnatal wound healing. The differential levels of TGF-β isoforms may provide either a predominantly antiscarring or profibrotic signal upon wounding depending on the gestational period. Lower expression of their receptors in early gestational skins may be a reason for the reduced ability to perceive ligands, ultimately leading to scar-free healing.

Notizen: It has been evidenced that the fat may have a potential to secret some growth factors or be a source of stem cells. So, we explore the effects of fat on healing of porcine skin wounds so as to provide a new method for clinical skin wound repair after injury.Forty-eight full-thickness skin wounds were produced on both sides of the back in 6 male minipigs (8 wounds in each animal). Then these wounds were randomly divided into 4 groups, which were saline control group, fat autografting group, basic fibroblast growth factor (bFGF) treatment group and epidermal growth factor (EGF) treatment group. At day 3, 7, 14 and 21 after wounding, the area and the volume of wounds were measured and the histological examination was performed to evaluate the velocity and quality of wounds healing in different groups.At day 3 and 7, the amount of granulation tissues and vessel density in fat treatment group were significantly more than that in other groups. Wound areas and volume in fat treatment wounds were markedly decreased in compared with those in other groups (P 〈 0.01). Regenerated epidermis in fat treatment group was thicker than that in other groups.These results confirmed that the wound healing velocity and quality in wounds treated with fat autografting were enhanced. It indicated that fat has a potential to accelerate velocity and improve the quality of wound healing after skin injury.

Notizen: To explore the effects of bone marrow mesenchymal stem cells (MSCs) on the quality healing of porcine skin wounds after burn injury so as to provide a new method for clinical skin repair in the future. Seventy-two deep-partial thickness burn wounds were produced on the back of 6 minipigs and randomly divided into 6 groups: saline control, MSCs treatment, MSCs plus bFGF treatment, MSCs plus EGF treatment, bFGF treatment or EGF treatment only. MSCs were isolated from porcine marrow and cultured in vitro. After labeling with BrdU, MSCs were autografted onto the skin wounds. At 7, 14, 21 and 42 days after injury, the area of the wounds were measured and the histological examination was performed to evaluate the velocity and quality of wound healing. At 1, 2 and 4 weeks after transplantation, immunohistochemical examinations were carried out to detect the positive staining of BrdU, cytokeratin and S-100 to evaluate the wound healing quality. The area of wounds was decreased at day 7 and most of these wounds were healed on day 21 after injury. There was no significant difference on the contraction rate among six groups. Histological examination demonstrated that the number of vessel and the expression density of S-100 in MSCs plus bFGF treatment wounds were significantly enhanced than that in other groups. MSCs autografting may benefit to enhance the wound healing quality in porcine skin, which may open a new way to reach a “perfect repair” after skin injury.