瘢痕组织中α-平滑肌肌动蛋白的表达与细胞凋亡的关系

目的:观察α-平滑肌肌动蛋白在瘢痕组织中的表达,了解病理性瘢痕形成过程中凋亡所扮演的角色及其与肌成纤维细胞在真皮中变化的关系。方法:瘢痕标本来自烧伤后来我院进行整形手术的病人,同时取病人手术供皮区的正常皮肤作为对照。 8例瘢痕组织标本 (含 2例愈合较为平坦的瘢痕和 6例增生性瘢痕组织)被分成增殖期和成熟期两组。运用caspase-3mRNA及其蛋白的表达及TUNEL方法检测瘢痕及正常组织中的凋亡细胞,并以免疫组化法检测瘢痕及正常皮肤真皮内α-平滑肌肌动蛋白单克隆抗体的表达。结果:瘢痕组织中细胞凋亡的数目与正常组织明显不同。瘢痕内的TUNEL标记阳性细胞数多于正常组织;增殖期瘢痕内的细胞凋亡的数目多于成熟期。增殖期TUNEL标记阳性的细胞多于平坦瘢痕,而成熟期两者无显著差别,Caspase-3mRNA及其蛋白的表达与TUNEL标记结果具有一致性。随着瘢痕组织的成熟,α-平滑肌肌动蛋白单克隆抗体的表达逐渐降低,平坦的瘢痕组织中的表现尤为明显;增生性瘢痕中,增殖期与成熟期之间无显著差别。结论:正常伤口愈合过程中,肌成纤维细胞暂时性的表达,可引起伤口的收缩,随着真皮再塑形,含有α-平滑肌肌动蛋白的肌成纤维细胞因凋亡而消失,而病理性的愈合结局可能是它持续表达的结果。     

Immunohistochemical localization of the proteoglycans decorin, biglycan and versican and transforming growth factor-β in human post-burn hypertrophic and mature scars

The distributions of the small proteoglycans, decorin and biglycan and the large proteoglycan, versican, in normal skin and post-burn hypertrophic and mature scars, were compared using monoclonal and polyclonal antibodies to the core proteins. Biglycan and verscan were virtually undetectable in normal dermis but readily seen in hypertrophic scars. Staining for decorin was strong throughout the dermis in normal skin but restricted to the deep dermis and a narrow zone under the epidermis in hypertrophic scar—areas which did not stain for versican. Decorin was absent or reduced in the nodules in these specimens. In mature post-burn scars, staining for all three proteoglycans demonstrated an intensity that was intermediate between that in normal dermis and that in the nodules of the hypertrophic scars. Transforming growth factor-β was present in the nodules of hypertrophic scars but the deep dermis of these specimens stained most intensely for this cytokine which was also found in the dermis of mature scars but was not detectable in normal dermis. The apparent co-distribution of decorin and transforming growth factor-β suggests that this proteoglycan may play an active role in the resolution of the scars. Changes in proteoglycan type and distribution could possibly account, at least in part, for the derangement of collagen and the altered physical properties of hypertrophic scar tissue.     

Keratinocyte-derived growth factors play a role in the formation of hypertrophic scars

In predisposed individuals, wound healing can lead to hypertrophic scar or keloid formation, characterized by an overabundant extracellular matrix. It has recently been shown that hypertrophic scars are accompanied by abnormal keratinocyte differentiation and proliferation, and significantly increased acanthosis, compared with normal scars. This study addressed the question of whether the development of normal and hypertrophic scars is regulated by differences in the growth factor profiles of both the epidermis and the dermis. The presence of interleukin-1alpha (IL-1alpha), IL-1beta, tumour necrosis factor-alpha (TNF-alpha), platelet-derived growth factor (PDGF), transforming growth factor-beta1 (TGF-beta1), and basic fibroblast growth factor (bFGF) was investigated in biopsies taken from breast reduction scars at 3 and 12 months following surgery. The samples were analysed by immunohistological methods and categorized as scars that remained hypertrophic (HH), became normal (HN) or remained normal after 12 months (NN). The epidermal expression of IL-1alpha was significantly increased in NN scars compared with HN and HH scars 3 and 12 months following operation, whereas the dermal expression showed no difference. PDGF was significantly increased in the dermis of normal scars after 3 months and in both the epidermis and the dermis of hypertrophic scars after 12 months. IL-1beta, TNF-alpha, TGF-beta and bFGF showed no differences. It is hypothesized that impaired production of keratinocyte-derived growth factors, such as IL-1alpha, leads to a decrease in the catabolism of the dermal matrix, whereas augmented epidermal PDGF production leads to increased formation of the dermal matrix in hypertrophic scars. These observations support the possibility that the epidermis is involved in preventing the formation of hypertrophic scars.     

Hypertrophic scar formation is associated with an increased number of epidermal Langerhans cells

The exact pathogenesis of hypertrophic scar and keloid formation is still unknown and a good therapy to prevent or treat these scars is lacking. Because immunological processes seem to be important in excessive scar formation, immunological cells and parameters were studied in a standardized breast reduction wound-healing model in the present study. Standardized scar samples were taken from infra-mammary breast reduction scars, 3 and 12 months following surgery. The samples were investigated for their number of mast cells, Langerhans cells, T-lymphocytes, and macrophages, and the presence of interleukin-4 (IL-4) and counter-regulating interferon-gamma (gamma-IFN), in relation to the scar's clinical appearance--normal or hypertrophic. In this study, hypertrophic scar formation was significantly associated with an increased number of epidermal Langerhans cells (p=0.0001) and significantly (p<0.05) increased expression of epidermal IL-4. No relationship was found between mast cell, T-lymphocyte and macrophage numbers or gamma-IFN staining and the formation of normal or hypertrophic scars. These results, combined with previous observation of abnormal keratinocyte behaviour in this context, indicate that the epidermal immune barrier plays an important role in the development of hypertrophic scars.     

Alterations in proteoglycan synthesis common to healing wounds and tumors.

Wound healing and tumor stroma generation share several important properties, including hyperpermeable blood vessels, extravasation of fibrinogen, and extravascular clotting. In both, the deposits of fibrin gel serve initially as provisional stroma and later are replaced by granulation tissue. Proteoglycans (PG) are also important constituents of the extracellular matrix, but their composition and role in healing wounds and tumor stroma generation are poorly understood. The authors used immunohistochemical and biochemical methods to investigate the dermatan sulfate proteoglycan (DSPG) and chondroitin sulfate proteoglycan (CSPG) composition of healing skin wounds and solid tumors. By immunohistochemistry, the great majority of normal guinea pig and human dermis stained weakly for CSPG and strongly for decorin. In contrast, the granulation tissue of healing skin wounds and scars stained intensely for CSPG and weakly or not at all for decorin; however decorin staining was restored to normal intensity after digestion with chondroitin ABC lyase, suggesting that decorin antigenic sites had been masked by glycosaminoglycan (GAG) chains. Like wounds, the stroma of several carcinomas (line 1 guinea pig, human breast, colon, basal cell, and squamous) stained strongly for CSPG and weakly or not at all for decorin, but decorin staining developed after chondroitin ABC lyase digestion. Thus healing wounds and tumor stroma express a common pattern of altered PG staining, adding another to the properties these pathologic entities share. Proteoglycans extracted from healing wounds after in situ labelling with [35S] Na sulfate contained more CSPG than normal dermis with significantly longer GAG chains. Granulation tissue also synthesized more DSPG than normal skin, with greater heterogeneity and longer GAG chains. These alterations in PG synthesis correlate with the cell proliferation, migration, and collagen synthesis that accompany wound healing and may provide clues to the mechanisms responsible for both wound healing and tumor stroma generation.     

脱细胞异体真皮与PELNAC联合烧伤瘢痕表皮移植治疗烧伤瘢痕的对比研究

目的 探讨脱细胞异体真皮联合自体深二度烧伤瘢痕表皮移植与皮耐克联合深二度烧伤瘢痕表皮移植在烧伤瘢痕治疗中的疗效比较。方法 选取2015年1月~2017年12月到我院治疗的烧伤瘢痕患者60例,进行随机分组,采用脱细胞异体真皮联合自体深二度烧伤瘢痕表皮移植治疗烧伤瘢痕患者（A组）30例,采用皮耐克联合深二度烧伤瘢痕表皮移植治疗烧伤瘢痕患者（B组）30例。分别比较两组的创面愈合时间,于创面愈合后6个月后进行随访并采用温哥华瘢痕量表（VSS）评价瘢痕情况以及参照ADL分级标准评定关节功能。结果 A组创面愈合时间为（12.07±4.30）d,短于B组的（22.00±3.85）d,差异有统计学意义（P＜0.05）;A组VSS评分为（4.10±3.27）分,B组为（4.40±3.80）分,两组差异无统计学意义（P＞0.05）。A组ADL评分:优5例,良12例,中10例,差3例;B组ADL评分:优4例,良11例,中10例,差5例;组间比较,差异无统计学意义（P＞0.05）。结论 脱细胞异体真皮联合自体深二度烧伤瘢痕表皮移植治疗烧伤瘢痕疗效,与皮耐克联合深二度烧伤瘢痕表皮移植治疗烧伤瘢痕疗效无明显差异,但脱细胞异体真皮联合自体深二度烧伤瘢痕表皮移植较皮耐克联合深二度烧伤瘢痕表皮移植创面愈合时间短,在临床有一定优势。     

Epidermal participation in post-burn hypertrophic scar development

 The reconstruction of epidermal architecture over time in normotrophic and hypertrophic scars in untransplanted, spontaneously healed partial-thickness burns has scarcely been studied, unlike the regeneration of epidermal grafts used to cover burn wounds and the regeneration of the dermis during hypertrophic scarring. The expression of markers of epidermal proliferation, differentiation and activation in normotrophic and hypertrophic scars in spontaneously healed partial-thickness burns was assessed and compared with the expression of these markers in normal control skin of healthy persons to determine whether hypertrophic scarring is associated with abnormalities in the phenotype of keratinocytes. Punch biopsies were taken both of partial-thickness burns after re-epithelialisation and of matched unburned skin. At 4 and 7 months post-burn, biopsies were taken of normotrophic and hypertrophic scars that had developed in these wounds. The biopsies were analysed using immunostaining for markers of keratinocyte proliferation, differentiation and activation (keratins 5, 10, 16 and 17, filaggrin, transglutaminase and CD36). We observed a higher expression of markers for proliferation, differentiation and activation in the epidermis of scars at 1 month post-burn than in normal control skin of healthy persons. There was a striking difference between normotrophic and hypertrophic scars at 4 months post-burn. Keratinocytes in hypertrophic scars displayed a higher level of proliferation, differentiation and activation than did normotrophic scars. At 7 months post-burn all keratinocyte proliferation and differentiation markers showed normal expression, but the activation marker CD36 remained upregulated in both normotrophic and hypertrophic scars. Surprisingly, in matched unburned skin of burn patients, a state of hyperactivation was observed at 1 month. Our results suggest that keratinocytes may be involved in the pathogenesis of hypertrophic scarring. Received: 16 September 1998 / Accepted: 28 September 1998     

乳糜化脂肪对移植于裸鼠背部皮下的人增生性瘢痕影响的实验研究

目的评价乳糜化脂肪对移植于裸鼠背部皮下人增生性瘢痕的影响。 方法选取18只BALB/c裸鼠;收集解放军总医院第四医学中心烧伤整形科行腹部、大腿外侧部脂肪负压抽吸手术获取的脂肪颗粒细胞及面、颈部手术切除的增生性瘢痕组织;脂肪颗粒细胞经过纳米转换头等操作处理为乳糜化脂肪;无菌条件下将增生性瘢痕组织切割成多块小样本;用眼科剪于各个裸鼠背部各作4个皮肤切口,稍做游离后将前述人增生性瘢痕组织块埋植入切口内,制备增生性瘢痕裸鼠动物模型。18只裸鼠按照随机数字表法分为3组,对照组,曲安奈德组和乳糜化脂肪组,每组6只裸鼠,24块瘢痕组织。移植后1周,对照组于每块移植瘢痕组织块内注射0.9%氯化钠溶液(0.05 mL/g);曲安奈德组注射曲安奈德注射液(0.05 mL/g);乳糜化脂肪组注射乳糜化脂肪(0.05 mL/g);之后每周各注射1次。移植后4周取材,比较移植前人增生性瘢痕组织块重量、移植后4周人增生性瘢痕组织块重量变化百分比;行苏木精-伊红染色和Masson染色,生物显微镜下观察组织形态学变化;比较Masson染色半定量分析阳性面积(天蓝色)占整体视野总面积的百分比。行免疫组织化学染色检测核心蛋白聚糖表达。对数据行单因素方差分析和Dunnett-t检验。 结果移植前,3组人增生性瘢痕组织块重量比较,差异无统计学意义(F＝26.230,P＝0.119),移植后4周,乳糜化脂肪组、曲安奈德组、对照组人增生性瘢痕组织块重量变化百分比分别为(73.2±15.9)%、(79.5±8.6)%、(87.0±14.9)%,比较差异有统计学意义(F＝16.680,P＝0.042),乳糜化脂肪组分别与对照组、曲安奈德组比较,差异均有统计学意义(t＝14.130、1.228,P＝0.010、0.099)。组织学观察可见,苏木精-伊红染色与Masson染色整体变化趋势相符：对照组真皮层可见大量胶原纤维及纤维细胞,胶原纤维排列紊乱;曲安奈德组真皮层见粗大胶原纤维,连续性及整齐度可;乳糜化脂肪组真皮层胶原纤维数量少且排列规律。Masson染色半定量分析：乳糜化脂肪组、曲安奈德组、对照组阳性面积(天蓝色)占整体视野总面积的百分比分别为(74.3±13.5)%、(80.9±9.0)%、(91.2±4.5)%,3组比较差异有统计学意义(F＝1.708,P＝0.025),乳糜化脂肪组分别与曲安奈德组、对照组比较,差异均有统计学意义(t＝13.130、7.806,P＝0.027、0.019)。增生性瘢痕中核心蛋白聚糖免疫组织化学分析结果：光学显微镜下可见曲安奈德组、乳糜化脂肪组显示出核心蛋白聚糖阳性染色结果,且乳糜化脂肪组染色强于曲安奈德组。对照组极其低地表达点、斑片状核心蛋白聚糖染色。乳糜化脂肪组、曲安奈德组、对照组核心蛋白聚糖表达量分别为0.021±0.010、0.025±0.012、0.088±0.058,3组比较差异有统计学意义(F＝32.160,P＝0.034),乳糜化脂肪组分别与曲安奈德组、对照组比较,差异均有统计学意义(t＝8.016、1.224,P＝0.048,0.027)。 结论乳糜化脂肪注射至人增生性瘢痕可降低成纤维细胞密度和数量,促进胶原排列、数量及形状正常化,改善胶原堆积等组织学特征。     

Activated keratinocytes in the epidermis of hypertrophic scars.

The etiology of hypertrophic scarring, a pathological end point of wound healing, is unknown. The scars most commonly occur when epithelialization has been delayed during, for example, the healing of deep dermal burn wounds. Hypertrophic scars are conventionally described as a dermal pathology in which the epidermis has only a passive role. In this study, the expression of keratin intermediate filament proteins and filaggrin has been investigated in the epidermis of hypertrophic scars and site-matched controls from the same patients. Hypertrophic scar epidermis was found to express the hyperproliferative keratins K6 and K16 in interfollicular epidermis in association with K17 and precocious expression of filaggrin. K16 mRNA was localized by in situ hybridization using a highly specific cRNA probe. In contrast to the immunohistochemical location of K16 protein, the K16 mRNA was found to be expressed in the basal cell layer of normal skin. In hypertrophic scars the mRNA distribution corroborated the abnormal K16 protein distribution. These results suggest the keratinocytes in hypertrophic scar epidermis have entered an alternative differentiation pathway and are expressing an activated phenotype. Activated keratinocytes are a feature of the early stages of wound healing producing growth factors that influence fibroblasts, endothelial cells, and the inflammatory response. We propose that cellular mechanisms in the pathogenesis of hypertrophic scarring are more complex than isolated dermal phenomena. The persistence of activated keratinocytes in hypertrophic scar epidermis implicates abnormal epidermal-mesenchymal interactions.     

Enhanced expression of transforming growth factor-beta type I and type II receptors in wound granulation tissue and hypertrophic scar.

In the present study we have analyzed and compared, by immunohistochemistry and in situ hybridization, the expression pattern of the R4/ALK5 transforming growth factor (TGF)-beta type I receptor (RI) and the TGF-beta type II receptor (RII) in normal human skin, in wounded skin at various stages during the transition of wound granulation tissue to scar, and in long-persisting post-burn hypertrophic scars. In normal human skin, expression of RI and RII was clearly visible in the epidermis, in epidermal appendages, and in vascular cells, although only a small number of dermal fibroblasts revealed detectable levels of TGF-beta receptor expression. In contrast, granulation tissue fibroblasts showed strong expression of both TGF-beta receptor types, although in normal-healing excisional wounds their density decreased during granulation tissue remodeling. However, in post-burn hypertrophic scars, RI- and RII-overexpressing fibroblasts were found in high densities up to 20 months after injury. From these findings we suggest that the repair process of deep wounds involves the transformation of a subset of fibroblastic cells toward an increased TGF-beta responsiveness and a transient accumulation of these cells at the wound site. In addition, our study provides evidence that excessive scarring is associated with a failure to eliminate TGF-beta receptor-overexpressing fibroblasts during granulation tissue remodeling, which leads to a persistent autocrine, positive feedback loop that results in over-production of matrix proteins and subsequent fibrosis.     

基质金属蛋白酶13和转化生长因子β1在瘢痕疙瘩和增生性瘢痕中的表达

背景：与瘢痕疙瘩和增生性瘢痕发生机制相关的基质金属蛋白酶13和转化生长因子β1信号传递通路研究多集中在体外成纤维细胞的培养上,而在组织中的相关研究少见报道。 目的：观察瘢痕疙瘩和增生性瘢痕中基质金属蛋白酶13和转化生长因子β1蛋白的表达。 方法：取自2004/2008唐山市工人医院烧伤整形科手术患者,瘢痕疙瘩54例,增生性瘢痕42例。选取同期45例因非感染手术切除的正常瘢痕组织作为对照组,选取同期45例正常皮肤组织作为正常对照组。应用流式细胞仪检测4组中基质金属蛋白酶13和转化生长因子β1的表达,分析两者的相关性。 结果与结论：瘢痕疙瘩和增生性瘢痕中转化生长因子β1的表达明显高于正常瘢痕组织和正常皮肤组织;正常瘢痕组织中转化生长因子β1的表达明显则高于正常皮肤组织,而基质金属蛋白酶13的表达与之相反。瘢痕疙瘩、增生性瘢痕和正常瘢痕组织中基质金属蛋白酶13和转化生长因子β1表达呈负相关。由此推测基质金属蛋白酶13和转化生长因子β1在瘢痕组织中异常表达,二者可能具有协同负向作用,共同参与病理性瘢痕的发生发展。     

Increased fibronectin production by cell lines from hypertrophic scar and keloid

Primary cell lines of fibroblasts from 8 tissues were established--three from hypertrophic scars (HS), one keloid (K) and four from the normal uninvolved dermis adjacent to each lesion. The objective was to quantify and compare all eight cell lines on the basis of fibronectin (FN) produced per cell and per total protein (PR). Two hypertrophic scars and their adjacent skin cell lines were evaluated by the ELISA method for FN and a micro Lowry assay for PR. The scar lines showed statistically significant increases in the amount of FN/cell compared to the cell lines from their adjacent normal dermis. The third hypertrophic scar and the keloid with their adjacent skin cell lines were assayed for FN and PR by radioimmunoprecipitation. Subconfluent cells were metabolically labeled with 35S-methionine for 20 hours. Harvested media and cell monolayers were assayed for radioactivity incorporated into FN and PR. The percentage of FN/PR was significantly higher in media for HS and K compared to the adjacent normal skin lines in the three passages tested. These results support our previous immunofluorescence studies and demonstrate that a fibroblast-type cell line from a hypertrophic scar or keloid produces more FN/PR over time than the normal fibroblast-type cell line from adjacent uninvolved dermis.     

Anomalous expression of HLA class II molecules on keratinocytes and fibroblasts in hypertrophic scars consequent to thermal injury.

Immunoperoxidase staining of skin sections obtained from 11 hypertrophic scars, six normotrophic scars and three samples of normal skin were performed using anti-HLA monoclonal antibodies (HLA-DR, -DQ, class I), anti-interleukin-2 receptor (IL-2R) and anti-CD1. Sections from all hypertrophic scars showed an anomalous expression of HLA-DR molecules on keratinocytes and fibroblasts. Moreover hypertrophic scars were characterized by dense infiltrates of IL-2R-positive cells and by the presence of abundant Langerhans (CD1+) cells in the epidermis and dermis. These results support the hypothesis that immunologic mechanisms play an important role in hypertrophic scarring and point to an involvement of cell-mediated immune phenomena.     

Hypertrophic scarring is associated with epidermal abnormalities: an immunohistochemical study

The role of epidermal keratinocytes in the early phases of normal unimpaired wound healing has been studied extensively. However, little is known about the cell biological processes in the epidermis and the basal membrane zone during the later phases of dermal matrix formation and remodelling of the scar tissue. This study investigated epidermal growth and differentiation and maturation of the basal membrane zone. Biopsies were taken from (clinically) hypertrophic and non-hypertrophic scars at 3 and 12 months after a breast- reduction operation. Tissues were analysed using immunohistochemical techniques. The data showed that epidermal abnormalities with respect to differentiation persist up to 3 months, as witnessed by the expression of cytokeratin 16. Remarkably, hypertrophic scars that remained hypertrophic throughout the period of analysis (up to 12 months) showed significantly more cytokeratin 16 expression at 3 months, when compared either with normal scars or with hypertrophic scars that became normal after 12 months. Staining for Ki-67 antigen, a marker for cell proliferation, revealed an increase in basal keratinocyte proliferation rate in 3-month-old hypertrophic scars compared with non-hypertrophic scars. After 12 months, this difference had disappeared completely and the number of cycling basal cells had returned to normal values. Three-month-old hypertrophic scars showed more acanthosis than non-hypertrophic scars of the same age, irrespective of whether they remained hypertrophic or became normal scars. After 12 months, this difference was no longer present. Staining for various heparan sulphate proteoglycan epitopes revealed that restoration of the basal membrane was incomplete at 3 months, but was complete at 12 months with respect to this component. No differences in the expression of several components of the basal membrane zone (heparan sulphate proteoglycan, laminin, tenascin) were noted between hypertrophic and non-hypertrophic scars. These data show that in the early phase of hypertrophic scarring, epidermal abnormalities are found compared with normal wound healing. In addition, early (3 months) epidermal abnormalities are associated with the clinical outcome at 12 months. These findings raise the possibility that the epidermal compartment is involved in the pathogenic process. Copyright © 1998 John Wiley & Sons, Ltd.     

Vascularization pattern in hypertrophic scars and keloids: a stereological analysis

Wound healing is a complex process that does not always occur harmoniously and may lead to pathological scar development, such as hypertrophic scars and keloids. Considering that vascularization can play a role in the development of these scars, and that the literature is controversial, we performed a stereological analysis of dermal for vessels of normal skin, normal scars, hypertrophic scars, and keloids. The parameters studied concerned vessels: surface density, length density; for vessels and myofibroblasts: volume density, in papillary and reticular dermis. The pattern of dermal vascularization in normal skin and normal scar showed no differences. In papillary demis, the number of vessels was higher in hypertrophic scars and keloids than in normal skin (p < 0.05). Vessels of hypertrophic scars were more dilated than those of normal skin (p < 0.01). In reticular dermis, vessels were present in higher amount in hypertrophic scars and keloids than in normal skin (p < 0.025; p < 0.001, respectively). The pattern of vascularization did not show any differences between hypertrophic scars and keloids. Our results show that hypertrophic scars and keloids have a distinct pattern of vascularization compared to normal skin and normal scars. This indicates that abnormal vascularization can be involved in the development of hypertrophic scars and keloids.     

DNA甲基化在病理性瘢痕中的作用研究

病理性瘢痕是指烧伤、创伤和手术等后创面过度修复引起,以胶原等大量细胞外基质产生与沉积失衡为特征的皮肤纤维增生性疾病,包括增生性瘢痕与瘢痕疙瘩等。随着对增生性瘢痕研究的不断深入,人们发现DNA甲基化在瘢痕形成的发生和发展过程中起着重要的作用。本文就DNA甲基化在病理性瘢痕中作用的研究进展进行综述。     

增生性瘢痕成纤维细胞中CyclinD1，CDK2，CDK4作用及与 细胞周期的相关性

背景：增生性瘢痕的发生和发展可能与细胞周期调节相关基因的异常表达有关。 目的：检测增生性瘢痕不同阶段细胞CyclinD1、CDK2和CDK4 mRNA及蛋白的表达,以及同一标本增生性瘢痕成纤维细胞的细胞周期运行中3者之间的一致性。 方法：采集32份增生性瘢痕标本,以增生性瘢痕形成时段分为3个月组、6个月组、1年组、2年组,各8份,并以8份正常真皮标本作为对照。利用实时荧光定量PCR法、Western blotting法检测标本中CyclinD1、CDK2、CDK4 mRNA及蛋白表达,流式细胞术检测成纤维细胞的细胞周期。 结果与结论：增生性瘢痕标本发展过程中CyclinD1、CDK2、CDK4 mRNA及蛋白表达水平由强至弱变化。3,6个月增生性瘢痕中成纤维细胞主要分布在S、G2 /M期;1,2年增生性瘢痕与对照组成纤维细胞多处于G0/G1期。表明增生性瘢痕不同时期CyclinD1、CDK2、CDK4各自的 mRNA和蛋白表达趋势基本一致,同时增生性瘢痕中成纤维细胞的细胞周期分布与这3个蛋白所执行的功能情况相对应。     

A comparative study of fibroblasts in healing freeze and burn injuries in rats.

In rats, the healing process of a full-thickness dermal freeze injury differs from that of a burn wound. Whereas burn wounds heal by wound contraction, the movement of surrounding normal skin over the defect, freeze wounds heal without wound contraction. That absence of contraction may be due to the freeze wound's lack of myofibroblasts, the cells reportedly associated with wound contraction. Myofibroblasts can be demonstrated histologically by staining the F-actin filaments of the stress fibers with NBD-phallacidin, a fluorescent reagent specific to F-actin filaments. Fibroblasts in normal dermis have no staining stress fibers. However, staining myofibroblasts are uniformly distributed in the granulation tissue of the healing burn and in the islands of granulation tissue between residual connective tissue fibers in the healing freeze wound. These residual dermal fibers were identified by their patterns of birefringence. Residual connective tissue matrix persists following cold trauma and acts like an internal splint. Burn trauma destroys cells and the connective tissue matrix, which is completely replaced with granulation tissue which undergoes wound contraction. Freeze trauma kills the cellular components of dermis, while some residual connective tissue fibers endure. This study shows that the connective tissue matrix can play an important role in the control of wound contraction.     

A quantitative ultrastructural study of collagen fibrils in human skin normal scars,and hypertrophic scars

The diameter-distribution of collagen fibrils in the dermis of human skin and scar tissue has been investigated. In samples of normal skin, normal scar, and hypertrophic scar, prepared for transmission electron microscopy, collagen fibrils were systematically random-sampled and their diameters measured. There was a statistically significant difference between the diameter-distribution of fibrils in the papillary and reticular layers of dermis in normal skin. A similar pattern was found in normal scar, but not in hypertrophic scar. © 1995 WiIey-Liss, Inc.     

Mechanical forces induce scar remodeling. Study in non-pressure-treated versus pressure-treated hypertrophic scars.

Reparative process of second and third degree burns usually results in hypertrophic scar formation that can be treated by pressure. Although this method is efficient, its mechanisms of action are not known. In this work, we have studied the histological organization of hypertrophic scars submitted to pressure. Skin biopsies were performed 2 to 7 months after the onset of treatment in two adjacent regions of the scar, non-pressure- or pressure-treated and analyzed by immunohistochemistry and transmission electron microscopy for extracellular matrix organization and cellular morphology. In non-pressure-treated regions, fibrillin deposits did not present the classical candelabra-like pattern under epidermis and were reduced in dermis; in pressure-treated regions the amount was increased compared to non-pressure-treated regions but the organization was still disturbed. In non-pressure-treated regions, elastin was present in patch deposits; in pressure-treated regions elastin formed fibers, smaller than in normal dermis. Tenascin was present in the whole dermis in non-pressure-treated regions, whereas in pressure-treated regions it was observed only under epidermis and around vessels, as in normal skin. alpha-Smooth muscle actin-expressing myofibroblasts were absent in normal skin, present in large amounts in non-pressure-treated regions, and almost absent in pressure-treated regions. The disturbed ultrastructural organization of dermal-epidermal junction observed in non-pressure-treated regions disappeared after pressure therapy; typical features of apoptosis in fibroblastic cells and morphological aspects of collagen degradation were observed in pressure-treated regions. Our results show that, in hypertrophic scars, pressure therapy restores in part the extracellular matrix organization observed in normal scar and induces the disappearance of alpha-smooth muscle actin-expressing myofibroblasts, probably by apoptosis. We suggest that the pressure acts by accelerating the remission phase of the postburn reparative process.