BMP-7 attenuates TGF-ß1-induced fibroblast-like differentiation of rat dermal papilla cells.

Dermal papilla cells (DPCs) show phenotypic plasticity during wound healing. The multipotency of DPCs is well recognized, but the signaling pathways that regulate the differentiation of these cells into fibroblasts are poorly understood. A preliminary experiment showed that transforming growth factor beta1 (TGF-ß1) can induce DPCs to differentiate into fibroblast-like cells, which suggests that DPCs may be a source of wound-healing fibroblasts. Bone morphogenetic protein-7 (BMP-7), a member of the TGF-ß superfamily, can prevent and reverse fibrosis by counteracting the TGF-ß1-mediated profibrotic effect. To determine whether BMP-7 attenuates the TGF-ß1-induced differentiation of DPCs into fibroblasts, we established an in vitro system for DPC differentiation and recorded the gene expression patterns that distinguished DPCs from fibroblasts. The proportion of fibroblast-like cells was significantly enhanced in DPCs treated with TGF-ß1, as evidenced by immunocytochemistry, flow cytometry, quantitative real-time reverse transcriptase polymerase chain reaction, and Western blot analysis. BMP-7 and TGF-ß1 administration substantially decreased fibroblast-like differentiation, indicating inhibition of TGF-ß1-induced differentiation. The antagonistic BMP-7- and TGF-ß1-activated signaling pathways can be used to promote wound healing or suppress hypertrophic scarring.

Basic fibroblast growth factor (bFGF) alleviates the scar of the rabbit ear model in wound healing.

Studies suggest a possible antiscarring effect of basic fibroblast growth factor (bFGF) during wound healing. However, little is known about the precise pathological mechanisms of bFGF. In particular, there is only limited information available about the mechanism of exogenous administration of bFGF to scar formation. To investigate the effect of bFGF on the hypertrophic scar in the rabbit ear model and to clarify the mechanisms of bFGF on treatment for scar in wound healing, the rabbit ear model of wound healing was created and treated topically with bFGF once daily for 3 months; then we examined the changes of macroscopic and histopathological characteristics of scars and the expression of collagen and collagenase-1 (matrix metalloproteinase-1). The results of macroscopic and histologic characteristics revealed a significant difference between scars treated with bFGF and control scars. The expression of collagen in the scars treated with bFGF was decreased, as compared with the scars treated with saline. Further study revealed that bFGF could remarkably enhance expression of matrix metalloproteinase-1. bFGF could improve the quality of wound healing and remarkably alleviate the scar in the rabbit ear model in wound healing, which suggests that bFGF exerted a net negative effecton scar formation in wound healing. The evidence should contribute to a better understanding of the biological activities of bFGF during hypertrophic scar formation.

Expression of Smad protein by normal skin fibroblasts and hypertrophic scar fibroblasts in response to transforming growth factor beta1.

BACKGROUND: Smad proteins are important intracellular mediators of transforming growth factor (TGF)-beta signaling. Little has been known about the specific relationship between TGF-beta and TGF-beta/Smad signaling in hypertrophic scars. OBJECTIVE: The objective was to investigate the expression of Smads and the specific relationship between TGF-beta and TGF-beta/Smad signaling in hypertrophic scars. METHODS: In this study, we initially determined the endogenous protein levels of Smad2 and Smad7 in hypertrophic scar fibroblast (HSFs) and normal skin fibroblast (NSFs). Second, we stimulated HSFs and NSFs with recombinant human TGF-beta1 for 24 hours to determine whether the TGF-beta1 could potentiate its effect by further stimulating the production of Smad by reverse transcription-polymerase chain reaction and Western blot analysis. RESULTS: When compared with NSFs, the endogenous expression of Smad2 in HSFs was up-regulated and TGF-beta1 could further stimulate the production of Smad2. Although the levels of Smad7 were similar between HSFs and NSFs, TGF-beta1 up-regulated the expression of Smad7 for NSFs only, with no discernible effect on HSFs. These changes were paralleled by a significant increase in cytoplasm-to-nuclear translocation of Smad2. CONCLUSION: These data substantiated the model of an autocrine positive loop in hypertrophic scars pathogenesis. The authors have indicated no significant interest with commercial supporters.

Experimental study on repairing of nude mice skin defects with composite skin consisting of xenogeneic dermis and epidermal stem cells and hair follicle dermal papilla cells.

OBJECTIVE: To investigate the influence of hair follicle dermal papilla cells (DPCs) on biological features of composite skin. METHODS: In the test group, xenogeneic acellular dermal matrix was employed as the frame, DPCs were seeded on the subcutaneous side, and epithelial stem cells onto the dermal papilla side of the dermal frame so as to construct a composite skin. In the control group, there was no DPC in the frame. The two kinds of composite skin were employed to cover skin defects on the back of the nude mice. Wound healing was observed 4 weeks after grafting and area was analyzed and contraction rate was calculated. The tissue samples in the grafted area were harvested for HE staining and the state of the composite skin was observed. The stress-strain curve of the sampled skin was measured, so as to calculate the maximal breaking power of the sample. The data were collected and statistically analyzed. RESULTS: HE staining indicated that the epithelial depth was increased (more than 10 layers of cells) in test group, with only 6-7 layers in control group. The skin contraction rate in test group on the 4th week after skin grafting (3.94+/-0.013)% was much lower than that in control group (29.07+/-0.018)% (P<0.05). It was indicated by biomechanical test that the stress-strain curve of the composite skin in the test group was closer to that of normal nude mice skin in comparison to that in control group. The maximal breaking force of the composite skin in test group was (1.835+/-0.035)N (Newton), while that in control group was (1.075+/-0.065)N (P<0.01). CONCLUSION: Reconstruction of epidermis in composite skin was promoted by dermal DPCs seeded in the dermal matrix frame. As a result, there was less skin contraction in the composite skin with DPCs, so that the biological characteristics of the skin were improved.

[Protective effects of urinastatin on organ function in patients with severe burn].

OBJECTIVE: To investigate the protective effects of urinastatin on organ function in severe burn. METHODS: Seventy-two cases with comparative severity in burn injury were randomly divided into urinastatin treatment group (n=36) and control group (n=36). Patients in control group received routine therapy, while those in treatment group received intravenous dripping of urinastatin twice a day for 5 to 7 days. The dosage of urinastatin was 300 kU in severe burns and 200 kU in moderate burns. Both polyvinylpyrrolidone iodine (PVP-I) and Jiedu Shaoshang cream were used for wound dressing. The clinical findings were assessed and variables indicating functions of internal organs, including liver (alanine aminotransferase), kidney (blood urea nitrogen, serum creatinine), heart (aspartate aminotransferase, lactate dehydrogenase, alpha-hydroxybutyrate dehydrogenase, creatine kinase, isoenzymes of creatinine kinase), and coagulation (prothrombin time, international normalized ratio, activated partial thromboplastin time, fibrinogen), as well as blood routine test, troponin, myoglobin, arterial blood analysis, bacteria culture were measured. RESULTS: In treatment group, vital signs and general condition were satisfactory at shock phase and peri-operative stages in all the patients. Edema of burn wound subsided rapidly. The 28-day mortality rate was 0. There was significant difference between the two groups (all P<0.05). CONCLUSION: Urinastatin has protective effects on multiple organs in severe burn injury.

[Influence of aerosols on the expression of cyclin B1, cyclin C and proliferating cell nuclear antigen in wound tissue healing of burned rat models].

OBJECTIVE: To investigate the influence of aerosols on the expression of cyclin B(1), cyclin C and proliferating cell nuclear antigen (PCNA) in wound tissue healing of burned rat models. METHODS: Sprague Dawley (SD) rats were inflicted as the deep partial thickness burn models. Rats were randomly divided into experimental group and control group. The experimental group were treated with aerosols. Samples were collected in 1 approximately 10 postburn days. Immunohistochemistry and image analysis methods were conducted to examine the expression of cyclin B(1), cyclin C and PCNA in both experimental and control groups. RESULTS: The expression of cyclin C in experimental group was detected in nucleus of skin basal cell on the second postburn day, increased evidently at the fifth days and sustained at high expression level up to the tenth days after treatment. The expression of cyclin C in experimental group was significantly higher than control group (P < 0.05). The expression of PCNA was first observed in skin basal cell nucleus and hair follicle cell nucleus in both experimental and control group on the third postburn day. The expression of PCNA increased evidently at the fifth days in experimental after treatment and that increased evidently at the seventh days in control group, which showed there were lots of active proliferation cell. And the difference of the expression of PCNA between experimental and control group was significant (P < 0.01). The expression of cyclin B(1) was detected in nucleus and cytoplasm of skin basal cell in both groups on the third postburn day, and no difference between the experimental and control group (P > 0.05). CONCLUSIONS: Aerosols can up-regulate the expression of cyclin C and PCNA in skin basal cell nucleus. Therefore the aerosols can accelerate wound tissue healing.

Effects of skin-derived precursors on wound healing of denervated skin in a nude mouse model.

Denervated skin could result in impaired healing of wounds, such as decubitus ulcers and diabetic foot ulcers. Other studies indicated that cutaneous fiber density is reduced after inner nerve transection and that neuropeptide level depletes after denervation, leading to reduced cell proliferation around the wound and thus wound healing problems. Recent studies have revealed that skin-derived precursors (SKPs), which form a neural crest-related stem cell population in the dermis of skin, participate in cutaneous nerve regeneration. We hypothesized that injecting SKPs into denervated wound promotes healing. A bilateral denervation wound model was established followed by SKP transplantation. The wound healing rate was determined at 7, 14, and 21 d after injury. Cell proliferation activity during wound healing was analyzed by proliferating cell nuclear antigen immunohistochemistry (IHC). Nerve fiber density was measured by S-100 IHC. The contents of nerve growth factor, substance P, and calcitonin gene-related peptide were examined by enzyme-linked immunosorbent assay. The rate of epithelization in the SKP-treated group was faster than that in the control group. Wound cell proliferation and nerve fiber density were obviously higher in the SKP-treated group than in the control group. In addition, the content of neuropeptides was higher in the SKP-treated group than in the control group during wound healing. In conclusion, SKPs can promote denervated wound healing through cell proliferation and nerve fiber regeneration, and can facilitate the release of neuropeptides.

HOXA9 regulates angiogenesis in human hypertrophic scars: induction of VEGF secretion by epidermal stem cells.

Hypertrophic scars are fibroproliferative disorders of excessive wound healing after skin injury. Vascular endothelial growth factor (VEGF)-induced angiogenesis plays a major role in fibrogenesis and hypertrophic scar formation. Over recent years, there has been a major interest in homeobox gene regulation of VEGF-VEGFR mediated angiogenesis in dermal tissue. In the current study, we investigated the role of homeobox genes in the epidermis, for their role in angiogenesis, with a focus on epidermal-mesenchymal interactions. As epidermal stem cells (ESCs) have a central role in epidermal homeostasis, we tested the hypothesis that these cells play a key role in the pathogenesis of hypertrophic scars through the HOXA9-VEGF/VEGFR signaling pathways. We found significant differences in the expression of homeobox A9 in hyperplastic scar tissue during different phases of development. These differences coincided with similar regulations in VEGF expression and with the distribution of ESCs. HOXA9 is expressed in cultured human ESCs in vitro. Antisense suppression of HOXA9 expression was found to suppress VEGF levels in ESCs. Together these findings indicate that homeobox A9 regulates the expression of VEGF in ESCs.

Directed differentiation of skin-derived precursors into fibroblast-like cells.

Skin-derived precursors (SKPs), which are located at skin's dermis, display multi-lineage potential and can produce both neural and mesodermal progeny in vitro. SKPs are considered to take part in dermal reconstruction and may be an important source of fibroblast during wound repairing. To explore the possibility of differentiation of SKPs into fibroblasts, the 3(rd) passage SKPs were treated with 0, 20, 40, 100, or 500 ng/ml human recombinant connective tissue growth factor (CTGF) for 48 h or treated with 100 ng/ml CTGF for 0, 24, 48, 72, or 96 h. Subsequently, a series of methods were to be used to observe cells immunocytochemistry changes under fluorescence microscope, to validate the mRNA expression change of collagen I, collagen III, fibroblast-specific protein 1 (FSP-1) and alpha smooth muscle actin (α-SMA) by quantitative real-time reverse transcriptase polymerase chain reaction (QRT-PCR), to analyze the expression of collagen I and collagen III protein by Enzyme-linked immunosorbent assay (ELISA), to semiquantitatively measure the expression of FSP-1 and α-SMA by western-blot. After differentiation, cells showed that positively staining for collagen I, collagen III, α-SMA, and FSP-1, which are markers for fibroblasts, but negative expression for neural precursors. The effects of CTGF on collagen I, collagen III, FSP-1 and α-SMA in SKPs were detected both on the transcriptional and posttranscriptional levels. These findings indicate that SKPs can be induced to differentiate into fibroblast-like cells with CTGF treatment that may be a key source of fibroblast in wound healing.

Effects of human bone marrow mesenchymal stem cells on burn injury healing in a mouse model.

OBJECTIVE: To investigate the feasibility and safety of human bone marrow mesenchymal stem cells (BM-MSCs) transplantation on the improvement of burn wound healing. METHOD: Human BM-MSCs were injected into the skin of the mouse models, and the new blood vessels growth, the engraftment of BM-MSCs and the speed of healing were observed. Moreover the body weight and activity were tested after BM-MSCs transplantation. RESULTS: We found that wound surface healing was significantly accelerated when BM-MSCs were applied to the wound surface in mice. Moreover, both the number and density of new blood vessels were increased in the BM-MSC-treated group. The engraftment of BM-MSCs was also investigated using GFP-labeled cells and no GFP-positive cells were observed in tissues other than the location of BM-MSC injection. We also found that both body weight and activity were quickly restored in BM-MSC-treated mice, and no tumor growth was found. CONCLUSION: The present results suggest that BM-MSC transplantation can effectively improve wound healing in a mouse model of burn injuries. Use of BM-MSCs might therefore facilitate development and improvement of burn injury treatments in future.

Fibroblast growth factor-binding protein facilitates the growth and migration of skin-derived precursors.

BACKGROUND: Fibroblast growth factors (FGFs) are important regulators of cell proliferation, migration, and differentiation during wound healing. FGF-binding protein (FGF-BP) plays a critical role in activating FGFs by releasing them from the extracellular matrix. Although previous studies have demonstrated a pivotal role for FGF-BP in wound healing and angiogenesis, little is known about the biologic effects of FGF-BP on skin stem cells that contribute to wound healing. OBJECTIVE: To investigate the effects of FGF-BP on the growth and migration of skin-derived precursors (SKPs). METHODS: FGF-BP was titrated to determine the optimal concentration that maximally stimulated cell proliferation. Cellular phenotype and telomerase activity were compared in the presence and absence of FGF-BP. The effect of FGF-BP on cell migration was observed by intravenously transplanting SKPs to adult mice. RESULTS: Cell proliferation was maximally stimulated by FGF-BP at a concentration of 10 ng/mL without changing the intrinsic characteristics of SKPs. Low levels of telomerase activity were detected, and FGF-BP decreased the rate at which telomerase activity was downregulated. In vivo, FGF-BP remarkably enhanced the migration of SKPs to skin lesion sites. CONCLUSION: FGF-BP exerts a positive effect on the growth and migration of SKPs, suggesting a potential role for SKPs in wound healing.

[Influence of skin-derived progenitor cell combining with hyaluronic acid on the wound healing of diabetic rat].

OBJECTIVE: To study the effect of skin-derived progenitor cell (SKP) combined with hyaluronic acid( HA) on the wound healing in diabetic rats. METHODS: SKP of Spraque-Dawley (SD) neonate rats were isolated and cultured and mixed with HA. The differentiation characteristics of SKP in the culture were observed. Sixty SD rats were injected intraperitoneally with 65 mg/kg streptozotocin( STZ) to induce diabetes. Two symmetrical full-thickness cutaneous wounds( 1.0 cm in diameter) were made on the back of each SD rat and randomly divided into A (n = 20, with treatment of 100 mircol SKP-HA) , B (n = 20, with treatment of 100 mirol HA) , and C ( n = 20, with treatment of DMEM/F12 culture medium) groups. Tissue samples from wound in each group were harvested on 1, 2, 3, 4 weeks after the treatment. Wound healing rate, changes in histomorphology, the content of hydroxyproline ( HYP) , and immigration of labelled SKP were determined and analyzed. RESULTS: SKP grew well when cultured with HA. The characteristics of SKP to differentiate into lipocyte, neuron, and neurogliocyte remained in the culture. Compared with that in C group, epithelization in the wounds of A and B groups appeared earlier. The wound healing rate in A group [ (72.1 +/- 2. 8)% ] and B group [ (53.7 +/- 2. 9)% ] were obviously higher at 2 post-treatment weeks(PTW) than that in group C [(42. 5 +/- 1.5)% ( P <0.05) , and that in A group was obviously higher compared with B and C groups at 3 PTW ( P < 0. 05 or 0. 01). The wound healing rates in A and B groups were (100. 00 +/- 0.00) % at 4 PIW, which were obviously higher than that of group C( P <0.01) . There was no obvious difference in the HYP content among the 3 groups at 1 PIW ( P > 0. 05) , but it was obviously higher in A and B groups than that in C group at 2,3,4 PTW( P <0.01) , and that in A group was significantly higher than that in B group at 3 and 4 PTW( P <0. 01). SKP survived well on the wound, and migrated towards the dermis as time elapses. CONCLUSION: SKP-HA composition can promote wound healing in diabetic rats.

[Isolation and differentiation characteristics of dermal multipotent stem cells from humans of different ages cultured in vitro].

OBJECTIVE: To study isolation, identification and differentiation characteristics of dermal multipotent stem cells from human of different age in vitro culture. METHODS: Skin samples( 1 cm x 1 cm) were harvested from fetus, infant, adult and elderly. The original clones were screened in stem cell medium. The diameter and number of clones were recorded. Analysis of each clone and determination of the expression of various related proteins were carried out. RESULTS: The number of suspended clones from normal skins of fetus, infant, adult and the elderly were (20. 1 +/-2. 5) x 102 , (15. 8 +/-5. 7) x 102, (10. 8 +/-1.3) x 10(2), (6.2 +/- 1.4) x 10(2), respectively ( P <0.01), while the diameter of the clones from them were (83 +/-12) microm, (55 +/- 10) microm, (46 +/- 12) Lm, (42 +/-8) microm, respectively ( P <0.05). Cloned cells from fetus, infant, adult and elderly could differentiate into neuron cell , neuroglia cell, smooth muscle cell, and adipocyte. The clones from fetus were inclined to differentiate into neuron cells, but those from infant were inclined to differentiate into neuroglia cells, and those from adult and elderly were inclined to differentiate into adipocytes. After 1 month of culture, the clone forming rate of the cells from fetus, infant, adult and elderly were 41. 1% , 25.5% ,17.7% ,15.2% , respectively. The individual clone cells also showed ability of multidirectional differentiation. Nestin, fibronectin, c-Myc, STAT3 and hTERT protein were expressed in all clones. CONCLUSION: Multipotent stem cells with multi-direction differentiation and proliferation can be efficiently isolated from dermis of human of different age in stem cell culture medium. The number, proliferation and differentiation of dermal multipotent stem cells can be affected by age.

[Effect of asiaticoside on the expression of transforming growth factor-beta mRNA and matrix metalloproteinases in hypertrophic scars].

OBJECTIVE: To investigate the effect of asiaticoside on the expressions of transforming growth factor (TGF)-beta mRNA, matrix metalloproteinases (MMPS) and tissue inhibitors of metalloproteinases (TIMPs) in postburn hypertrophic scars. METHODS: Nine specimens of postburn (5-8 months) hypertrophic scars with asiaticoside treatment and 9 without asiaticoside treatment were collected for testing the expressions of MMPS, TIMPs, type I and III collagen and TGF-beta mRNA by immunohistochemistry and in situ hybridization methods, followed by image analysis of the results. RESULTS: The expressions of TGF-beta mRNA and MMPS/TIMPS were all detected in the fibroblast cytoplasm. The expression of TGF-beta(1) mRNA in asiaticoside-treated scars was significantly lower than that in scars without asiaticoside treatment (P<0.01). In contrast, the expression of TGF-beta(3) mRNA was significantly higher in asiaticoside group (P<0.05). The expression of TIMP1 in asiaticoside group was significantly lower than that in non-asiaticoside group (P<0.01), and the expression of type I collagen in asiaticoside-treated scars was lower than that in non-asiaticoside-treated specimens (P<0.05), but the expression of MMP(1), MMP(2) and TIMP(2) and type III collagen exhibited no significant differences between the two groups (P>0.05). CONCLUSION: Asiaticoside can down-regulate TGF-beta(1) mRNA and TIMP(1) expressions and up-regulate TGF-beta(3) mRNA expression in postburn hypertrophic scars, and is also capable of decomposing the products of type I collagen, contributing to the reduction of hypertrophic scar formation.

[Study on the regular pattern of the distribution of skin epidermal stem cells in the different parts of a healthy human body].

OBJECTIVE: To investigate the regular pattern of the distribution of skin epidermal stem cells (ESCs) in the different parts of a healthy human body, and to evaluate the feasibility of the identification of ESCs by P63 and CD29 with single and double labeling. METHODS: Full-thickness skin samples from 21 parts (including scalp, dorsum of foot, sole of foot, pubic region, and scrotum) of 5 healthy persons were harvested for the study. Immunohistochemistry method with biotin-streptavidin-horseradish peroxidase (SP) was employed with P63 and CD29 as the first antibody to carry out single and double labeling. The staining results were subjected to image analysis. The distribution of the ESCs in the skin from the above parts was observed and expressed as positive unit (PU) value. RESULTS: It was found by P63 single labeling and P63 and CD29 double labeling that the PU value in the dorsum of foot was the lowest while that in the scalp was the highest among all the parts of a healthy body. It was also found by CD29 single labeling that the PU value in the dorsum of foot was the lowest [(11.9 +/- 1.5)%] while highest in the scalp [(29.1 +/- 5.0)%]. The PU value in the hairy region of a human body was evidently higher than that in the non-hairy region (P < 0.01), when examined by P63 and CD29 single and double labeling. But there was no difference in the PU values between the trunk and limbs by means of P63 and CD29 single and double labeling (P > 0.05). CONCLUSION: There are more ESCs in the skin from the scalp, mons pubis and scrotum than other parts of the body. Single P63 or CD29 labeling exhibits higher sensitivity but lower specificity in the identification of ESCs. While the double labeling method exhibits higher specificity but lower sensitivity. Above all, it seems that the double labeling may be a simple and effective method for the identification of ESCs.

[Effects of citrus reticulata blanco extract on fibroblasts from human hypertrophic scar in vitro].

OBJECTIVE: To investigate the effects of citrus reticulata blanco extract on the proliferation and collagen metabolism of fibroblasts from human hypertrophic scar. METHODS: Human hypertrophic scar fibroblasts from two burn patients obtained from plastic surgery were cultured in vitro and divided into experimental group (n = 12, with basic culture medium and 2.5, 5.0, 10.0,25.0 mg/L citrus reticulata blanco extract, respectively, 3 bottles for each concentration of citrus reticulata blanco extract ), control group 1 (n = 3, with basic culture medium) , and control group 2 ( n = 3, with basic culture medium and 5% ethyl alcohol). The cell proliferation in each group was observed with MTT method, then the inhibition rate was calculated. Apoptosis and its index ( AI) in each group were determined after TUNEL staining . The changes in the content of ICTP and PINP in each group were observed by radioimmunity. RESULTS: The inhibition rate in the experimental group with the citrus reticulata blanco extract in concentration of 2. 5, 5.0, 10.0, 25. 0 microg/ ml were (7. 100+/-0.038)% , (8. 100+/- 0. 048)% , (10. 900+/-0. 055)%, (15.900+/-0. 097) %, respectively, which were significantly higher than those in other two groups ( P <0.05 ). The Al (69. 7% , 71.7%, 86.4% , 95.2% ), ICTP [(17.2+/-0.6), (18.3+/-0.6), (19.8+/-0.5), (23.2+/-0.6) microg/L] and PINP [ (101.7+/-1.4) , (107. 8+/-1. 1) , (111.6+/-1.2) , (124. 6+/-1.3) microg/L] in experimental group with the citrus reticulata blanco extract in concentration of 2.5, 5.0, 10.0 , 25.0 mg/L were also obviously higher than other two control groups( P <0.05) ,but these indices in control 1 group were similar to those in control 2 group( P >0. 05). CONCLUSION: The citrus reticulata blanco extract might be beneficial for the management of hypertrophic scar through inhibition of the proliferation of fibroblasts in hypertrophic scar, by promoting apoptosis and collagen degradation.

[Clinical study and pathological examination on the treatment of deep partial thickness burn wound with negative charge aerosol].

OBJECTIVE: To investigate the effect of negative charge aerosol (NCA) on the treatment of burn wound. METHODS: Patients with superficial or deep partial thickness burn only were enrolled in the study, and they were randomly divided into trial group (T, including 180 cases of superficial thickness burn and 100 cases of deep partial thickness burn), control group (C, including 30 cases with superficial thickness burn and 30 with deep partial thickness burn), and self control group (SC, including 10 cases with superficial thickness burn and 10 with deep partial thickness burn). The patients in T and SC groups were treated with NCA for 1.5 hours, 1-2 times a day, from 6 postburn hour (PBH) to 2 postburn day (PBD), while those in C group received conventional treatment. For those in SC group, some of the wounds were covered with sterile schissel, while other wounds without schissel covering. The general changes in the wounds during NCA treatment were observed, and bacterial culture before and after NCA treatment was performed. The healing time was recorded and the blood biochemical parameters were determined. Rat model with deep partial thickness scald was established, and the rats were also divided into T and C groups, and received treatment as in human. Tissue samples were harvested from the wounds of rats in the 2 groups before and 1, 2, 3 weeks after treatment for pathological examination. RESULTS: There was no infection and little exudation in the patients in T group. No bacteria were found in the wound before and after NCA treatment. The healing time of the wounds of patients with superficial and deep partial thickness burn in T group was 6.3 +/- 1.6 d and 15.1 +/- 3.1 d, respectively, which was obviously shorter than those in C group (11.3 +/- 1.4 d and 21.2 +/- 1.4 d, P < 0.01). In SC group, the healing time of those with sterile schissel coverage was also significantly shorter than those without covering (P < 0.01). There was no obvious change in the liver and kidney functions and blood biochemical parameters among the patients. Pathological examination showed that the skin structure was almost recovered in the rats in T group 3 weeks after treatment, while those in C group was not. CONCLUSION: Negative charge aerosol is safe and effective in promoting wound healing of the patients with partial thickness burns.

[Clinical significance of the predominant bacterial strains on burn wound during early postburn stage].

OBJECTIVE: To investigate the clinical significance of the predominant bacterial colonization on burn wound in our department during recent years, so as to help select optimal antibiotics in burn patients with severe infections. METHODS: This bacterial investigation was carried out in 215 cases of severely burned patients. The bacterial culture and the drug susceptibility test were carried out. RESULTS: (1) One hundred and twenty-two strains of bacteria were cultured, in which 28 strains (23%) were Staphylococcus with negative coagulase, 27 (22%) S. aureus, 17 (14%) Pseudomonas aeruginosa, 11 (9%) Escherichia coli, 10 (8%) Enterobacter, 9 (7%), enterococci, 3 (2.5%) fungi, and 17 (14.5) other bacteria. (2) The resistance of S. aureus to ampicillin, oxacillin and amoxicillin/clavulanic acid was 81%, 38% and 31%, respectively. 11% and 16% of Pseudomonas aeruginosa resistant to Imipenem and Ceftazidime, respectively. (3) The sensitivity of G + cocci to vancomycin and norvancomycin, Chloramphenicol, Teicoplanin, Trimethoprim/Sulfamethoxaz, Rifampin was 100%, 100%, 100%, 94% and 88% respectively, and the Gram-negative bacilli to Meropenem, Imipenem, Amikacin, Cefepime, Cefoperazone/Sulbactam, Ceftazidime were 91%, 90%, 81%, 78%, 71% and 70%, respectively. Furthermore, the sensitivity of Pseudomonas aeruginosa to Cefoperazone/Sulbactam, Ceftazidime, Tobramycin, Meropenem, Amikacin, Ciprofloxacin, Amikacin, Cefepime were between 82% and 91%. MRSA was very sensitive to both vancomycin and norvancomycin. CONCLUSION: The results suggested that Staphylococcus with negative coagulase and S. aureus were the predominant bacteria and Pseudomonas aeruginosa ranked second. The resistance of these bacteria to antibiotics was on the increase. Moreover, colonization of enterococcus and fungi on burn wound increased recently, which were scarce before. This implied the importance of rational and correct use of antibiotics during early postburn stage.

[Comparison of the effects of rhEGF with rhbFGF on the acceleration of wound healing].

OBJECTIVE: To investigate the mechanism and the accelerating effect of rhEGF and rhbFGF on wound healing. METHODS: Twelve New Zealand rabbits with 72 incised wounds on ventral side of 24 ears were randomly divided into two therapeutic groups (rhEGF of 10 ug/cm(2) and rhbFGF of 100 AU/cm(2)) and a control group (1% silver sulfadiazine cream, SD-Ag). The general conditions of the wound healing was observed grossly. Biopsies were harvested at different time points for the pathomorphological examination, the electron microscopic examination, and for assessment of integrin beta1 mRNA expression by in situ hybridization. RESULTS: The expressions of integrin beta 1 mRNA in two therapeutic groups were significantly higher than that of control group. The quality of the wound healing was improved in therapeutic group with its healing time shortened when compared with that in control group (P < 0.05). There was an obvious difference in the number of fibroblasts and capillary gemmules between the therapeutic and control groups (P < 0.05). CONCLUSION: The wound healing and quality could be improved by both rhEGF and rhbFGF, but rhbFGF seemed better to be employed during the early and middle stages of the wound repair for the growth of granulation tissue, while rhEGF should be applied at the late stage of wound repair to accelerate the re-epithelialization of the wound. Combined application of rhEGF with rhbFGF according to time effect could be more beneficial to the wound repair.

[A preliminary study on the identification and distribution of epidermal stem cells in different degrees of burn wounds in scalded rats].

OBJECTIVE: To investigate the distribution of epidermal stem cells (ESCs) in different degrees of burn wounds in scalded rats. METHODS: Thirty-two Sprague-Dawley (SD) rats were employed in the study. First degree (I), shallow (shallow II) and deep partial thickness (deep II) and full thickness burn wounds (III) were created on the rat skin. Burn wound samples were harvested at 24 postburn hours (PBHs) from all the wounds and were processed to tissue slices. The tissue slices were stained by immunohistochemistry technique. The expression and distribution of ESCs in different degrees of burn wounds were observed with integrins alpha 2 beta 1 and keratin 10 (K10) as first antibodies. RESULTS: K10 positive cells were found to distribute in the strata spinosum, granulosum and lucidum in the first degree burn wound (I) with large amounts of integrins alpha 2 beta 1 positive cells in the residual basal layer and skin appendages (hair follicles) in shallow partial thickness burn wound (shallow II degree), and there were less integrins alpha 2 beta 1 positive cells in the remaining skin appendages in deep dermis in deep partial thickness burn wound (deep II degree). Finally, integrins alpha 2 beta 1 positive cells were sparsely found in the III degree burn wound. CONCLUSION: The distribution of ESCs in burn wounds was closely related to the depth of burn wound. The residual ESCs might be the origin of burn wound regeneration and reepithelization.