The scar formation and chronic ulcer development are the iain sequelae faced by surgeons in the treatmemt of wounds. Therefore,the prevention and treatment of these sequelae are the main tasks for clinicians.In this paper,the current research concerning both sequelae is reviewed.The authors emphasize that the use of some high technologiesl, such as stem cell technology, clone technology and tissue engineering may bring the hope in improving the treatment and prevention of these sequelae.

Humans ; Reconstructive Surgical Procedures ; adverse effects ; Surgery, Plastic

Objective To investigate the inductive role of traumatic microenvironment in dedifferentiation of epidermal cells and explore the potential role of Wnt signaling pathway in this biological process. Methods The sheets of human foreskin were digested overnight after removal of adipose tissue, and then the epidermis was separated from the dermis. The separated epidermis sheets were repeatedly adhered to type Ⅳ collagen and flushed to remove the epidermal stem cells. The obtained epidermis sheets were transplanted onto the full-thickness skin wounds on the back of BALB/c nude mice, five days after which the cell lineage was evaluated by immunohistochemistry and the expressions of Wnts and downstream components in the grafted epidermal sheets examined by RT-PCR and Western blot. Results The cells in the basal layer of full-thickness epidermal sheets were positive for CK19 and β1 integrin and negative for CK10. While the cells in uhrathin epidermal sheets treated with type Ⅳ collagen were fully positive for CK10. Five days after transplantation of the ultrathin epidermal sheets, cells negative for CK10 but positive for CK19 and β1 integrin emerged at the wound-neighboring side of the skin grafts. At the same time, the expressions of Wnt-10b, Wnt-4 and Wnt-7a mRNA were increased by about 3.1-fold, 2.2-fold and 1.4-fold independently after transplantation. Furthermore, the expressions of β-catenin and β-catenin target genes (cyclin D1 and c-myc) were elevated by about 3-fold, 1.5-fold and 2-fold respectively in the grafted epidermal sheets (P < 0.01). Conclusion Traumatic microenvironment can induce epidermal cell dedifferentiation, when the Wnt/β -catenin signaling pathway may play an important role.

To identify the stem cell islands in regenerated epidermis, the same biopsies used in our previous experiments were used in this study. CD87 immunohistochemicy and PAS staining were used. The scant CD87 positive cells could be found in basal membrane. Also, the positive staining of PAS could be seen in the basal membrane in both normal and regenerated epidermis. No CD87 positive cells were found in the spinous and granular layers. The results indicate that the error in metrology could be excluded from both CD87 immunohistochemicy and PAS staining, and that the stem cell islands may come from the cell reversion in regenerated epidermis.

To gain insight into the mechanisms of an age related difference in ability of wound healing, the characteristics of stem cell differentiation in skins from fetus, child and adult were investiga ted. Integrin ? 1 and keratin 19 (K19) were used as the biochemical markers for stem cells and transit amplifying cells. Biopsies were taken from fetus (22～24week gestational age), children (4～12year) and adults (35～53year). Immunohistochemistry was used. As for the immunostainings of fetal tissue sections, integrin ? 1 and K19 expressions were observed in all epidermal basal cells. In children skin, the ratio of integrin ? 1 and K19 positive cells in the epidermal basal layer was 60%～80%. In adults, the ratio in the epidermal layer decreased. These results indicate that fetal skin epidermis contains a large number of stem cells and transit amplifying cells, and the proportion of stem cells and transit amplifying cells decreases with age after birth, which maybe a reason of the age associated difference in ability of wound healing.

To investigate the effects of basic fibroblast growth factor (bFGF) on intracellular free Ca 2+ of heating injury, and observe the relationship between mitogen activated protein kinases(MAPKs)signal pathways and Ca 2+ mobilization. Cultured human fibroblasts were heated at 45?C for 10min, then divided into four groups :①basic fibroblast growth factor (10ng/ml) treatment; ②preincubated cells with PD98059 (10?mol/L) for 30 min followed by bFGF (10ng/ml); ③preincubated cells with SB203580 (10?mol/L) for 30min followed by bFGF (10ng/ml); ④preincubated cells with PD98059 (10?mol/L) and SB203580 (10?mol/L) for 30min followed by bFGF (10ng/ml). The cells were incubated with fluorescence Ca 2+ dye fluo 3/AM at 37 C for 30min, then measured by using laser scanning confocal microscope. The results showed fluorescent intensity of fibroblast heating injury was weak, the concentration of intracellular free Ca 2+ increased after stimulation with bFGF treatment. PD98059 and SB203580 could induce calcium oscillation. A rapid decrease of fluorescent intensity was observed after cells were preincubated with PD98059 and SB203580 at the same time. bFGF induced an increase of cytoplasmic and intracellular free Ca 2+ concentrations. It is suggested that MAPKs signaling pathway has a feedback regulation for free Ca 2+ mobilization.

Wound repair is a complex biological process and great progresses have been achieved during the last ten years because of the integration of molecular biology and traumatology. However, some fundamental principles in these fields, which are closely related to developmental biology and comparative biology have not been fully understood. Therefore, more attention should be paid to the incorporation basic knoweldge with technology of developmental biology and comparative biology in the research of wound repair before better understanding and new discoveries are achieved in this field.

To investigate the different expression of Fas, Fas L and Caspase 3 in hypertrophic scars and normal skins in order to explore their influences on scar formation, the expression intensity and distribution of Fas, Fas L and Caspase 3 were detected by immunohistochemistry and pathological methods in 8 cases of hypertrophic scars and 8 cases of normal skins. In normal skins, Fas and Fas L were mainly located in the cellular membranes and cytoplasms of epidermal cells and some fibroblasts. Caspase 3 was mostly distributed in epidermal basal cells and some fibroblasts. In hypertrophic scars, Fas and Fas L were principally existed in the membranes and cytoplasms of epidermal keratinocytes. The positive cellular ratio of two proteins was significantly reduced ( P

The purpose of this study was to investigate the localization and expression characteristics of phosphorylated form of extracellular-signal regulated-protein kinasel/2 (p-ERKl/2), Ras and C-fos in skin at different development stages and to explore their potential biological significance. Immunohistochemistry and pathological methods were used to detect the expression intensity and distribution of p-ERKl/2, Ras and C-fos in skin of 8 fetuses with different gestational ages (13 to 31 weeks) and 8 adults. Positive immunohistochemical signals of p-ERK1/2, Ras and C-fos. could be found in fetal and postnatal skins. Along with the increment in gestational age, the positive cell rates of p-ERK1/2, Ras and C-fos in the skin elevated progressively. In skins derived from the fetus of late-trimester pregnancy and adult, the positive rates of these three proteins were significantly increased in comparison with skin from the early-trimester fetus (P

Localization and expression of two subunits (IGF ⅠR? and IGF ⅠR?) of insulin like growth factor Ⅰ receptor and phosphorylated tyrosine proteins (P Tyr) in skins at different developmental stages were studied in order to explore their potential biological significance. Immunohistochemistry and pathological methods were used to detect the expression intensity and distribution of IGF ⅠR?, IGF ⅠR? and P Tyr in skins of 12 fetuses with different gestational ages and 8 adults. The results showed that positive immunohistochemical signals of IGF ⅠR?, IGF ⅠR? and P Tyr could be found in fetal and adult skins. Along with growth and development of the fetus, the positive cell rates of IGF ⅠR?, IGF ⅠR? and P Tyr in skins elevated progressively. In adult skins, IGF ⅠR was mainly located in the cell membrane of epidermal cells, while P Tyr was chiefly distributed in epidermal cells and some fibroblasts. These results suggested that IGF ⅠR and its mediating signaling pathway might be involved in cutaneous development at embryonic stage, in cutaneous structure and function maintenance, and in wound healing at postnatal stage.