Effects of microporous porcine acellular dermal matrix combined with bone marrow mesenchymal cells of rats on the regeneration of cutaneous appendages cells in nude mice / 中华烧伤杂志

<p><b>OBJECTIVE</b>To observe the effects of microporous porcine acellular dermal matrix (ADM) combined with bone marrow mesenchymal cells (BMMCs) population containing bone mesenchymal stem cells (BMSCs) of rats on the regeneration of cutaneous appendages cells in nude mice.</p><p><b>METHODS</b>Split-thickness dermal grafts, 20 cm×10 cm in size and 0.3 mm in thickness, were prepared from a healthy pig which was sacrificed under sanitary condition. Laser microporous porcine ADM (LPADM) was produced by laser punching, hypertonic saline solution acellular method, and crosslinking treatment, and nonporous porcine ADM (NPADM) was produced by the latter two procedures. Then the appearance observation, histological examination and scanning electron microscope observation were conducted. BMMCs were isolated and cultured from tibia and femur after sacrifice of an SD rat. Osteogenic and adipogenic differentiation experiments were conducted among the adherent cells in the third passage. Then they were inoculated to LPADM and NPADM to construct BMMCs-LPADM and BMMCs-NPADM materials. Twenty-one healthy nude mice were divided into BMMCs-LPADM+NPADM group (A, n = 6), LPADM+split-thickness skin graft group (B, n = 6), BMMCs-LPADM+split-thickness skin graft group (C, n = 6), BMMCs-NPADM+split-thickness skin graft group (D, n= 3) according to randomized block. After anesthesia, a 2 cm×2 cm full-thickness skin defect reaching deep fascia was reproduced in the middle of the back of each nude mouse, and a split-thickness skin graft of the same size was obtained, and then prepared skin grafts were transplanted to cover the wounds respectively. On post transplantation day (PTD) 5, 7, and 14, local condition and adverse effects observation was conducted; one nude mouse was sacrificed each time to harvest all the transplant for tissue structure observation with HE staining. On PTD 7 and 14, neonatal skin appendages in corresponding composite materials were observed with transmission electron microscope.</p><p><b>RESULTS</b>(1) LPADM and NPADM appeared to be porcelain white, soft, and flexible. No cellular component was observed in acellular dermal matrix. Scanning electron microscope showed that the collagen fibers were orderly arranged. LPADM had microporous structure. (2) Cells in the third passage were orderly arranged with the shape similar to fibroblasts with high growth speed. (3) Induced differentiation experiments showed that cells could differentiate into osteoblasts and adipocytes. (4) On PTD 5, the NPADM in group A was dry in part; skin grafts in group D were dry and necrotic, and there was no infection and inflammation in groups A and D; skin grafts in groups B and C survived. On PTD 7 and 14, the overlaying material in group A was black, dry, and hard in part; the skin grafts in group D turned to be completely black, dry, and necrotic, and pale yellow clear exudate was found in subcutaneous area; there was no obvious purulent discharge in groups A and D; the appearance of skin grafts in groups B and C was close to the surrounding skin. (5) On PTD 5 and 7, in groups A, B, and C, vascularization was apparent in the pores of dermal matrix, and red blood cells could be found. In group D, skin grafts were dry and necrotic. On PTD 14, in groups A, B, and C, the pore structure of dermal matrix was fully vascularized in which a large number of red blood cells were visible. In group A, the microporous dermal matrix survived, but the overlaying NPADM was not attached closely. In groups B and C, the skin grafts were closely connected to the dermal matrix, and no cutaneous appendages were observed. In group C, special monolayer cells were found at the junction between skin graft and dermal matrix. (6) Skin grafts in group D failed to survive; they were not observed with the electron microscope. On PTD 7, there were no significant differences among groups A, B, and C. On PTD 14, no sebaceous gland-like cell or sweat gland-like cell and no newborn nerve ending were observed in skin grafts in groups A and B, in spite of the immigration of fibroblasts. In group C, a large number of new capillaries were observed at the junction between the skin graft and dermal matrix; rough endoplasmic reticulum of fibroblasts proliferated exuberantly; newborn unmyelinated nerve endings were observed; single free sweat gland-like cells and sebaceous gland-like cells were observed in superficial dermal matrix.</p><p><b>CONCLUSIONS</b>LPADM, which provides a "cell niche-like" micro-environment for the migration and differentiation of the BMMCs population, when combining with the split-thickness skin graft, can induce exogenous differentiation of BMSCs in vivo, thus achieving the reconstruction of skin appendages.</p>

Analysis of correlation factors affecting the incidence of burn shock / 中华烧伤杂志

<p><b>OBJECTIVE</b>To analyze the correlation factors affecting the incidence of burn shock, so as to provide guidance for the clinical treatment of shock after burns.</p><p><b>METHODS</b>Retrospective analysis of clinical data of 15 624 patients hospitalized in our department from 1973 to 2005 was undertaken . The incidence of shock during every 10 years, as well as the relationship between shock incidence and age, burn area, interval between injury and hospitalization, and complications were analyzed statistically.</p><p><b>RESULTS</b>The incidence of shock during 1973-1980, 1981-1990, 1991-2000 and 2001-2005 periods was 14.69%, 13.50%, 9.38% and 7.88%, respectively, and there was significant difference of shock incidence between each 10 years and its succeeding period (P < 0.01). The occurrence of shock was closely related to age, length of time between injury and hospitalization, and burn area. The shock incidence of children under 7 years old or elderly more than 60 years old was obviously higher than other age groups, and there was positive relationship between burn area and shock incidence. Moreover, the shock incidence of the patients hospitalized later than 4 to 12 hours after burn shock was also markedly higher than those hospitalized earlier (P < 0.01). In addition, the incidence of sepsis, alimentary tract hemorrhage, acute renal failure, pulmonary failure, and cardiac failure in patients with shock was obviously higher than those without shock (P < 0.01).</p><p><b>CONCLUSION</b>For the children and aged people, special attention should be paid in the prevention and resuscitation of burn shock. Early fluid resuscitation is vital for the prevention of organ complication, and it is beneficial to promote wound healing.</p>

Isolation, culture and identification of human epidermal stem cells / 上海第二医科大学学报

Objective To explore a method for isolation and culture of human epidermal stem cells. Methods Epidermis was obtained by digesting human foreskin with Dispase Ⅱ and Trypsin-EDTA.After suspension on the epidermal stem cell medium (ESCM), these single epidermis cells were inoculated onto human collagen Ⅳ-coated flasks and cultured at 37 ℃ in a humidified atmosphere containing 5% CO_2 for 10 min. The nonadherent cells were rinsed off 10 min after inoculation, and the adherent cells continued to be cultured after enriching and abstraction by type Ⅳ collagen. The cell growth was observed through inverted microscope, and the cell cloning efficiency and time of clone sustain were also detected. Immunocytochemistry was used to observe the expression of ?_1-integrin and keratin 19(K19). Keratinocytes were served as controls. Results It was revealed by histological observation that colonies were formed 24 hours after inoculation. The isolated and cultured cell cloning efficiency was higher and the time of clone sustain was longer than that of the control group. Positive expression of ?_1-integrin and K19 of cultured cells was detected by immunocytochemistry. Conclusion Adult epidermal stem cells could be successfully isolated and cultured by adhension with type Ⅳ collagen and culture with ESCM.