CD44及其配体HA在瘢痕及胎儿皮肤成纤维细胞中表达的比较研究

目的:探讨CD44及其配体透明质酸(HA)在瘢痕及中孕胎儿皮肤成纤维细胞中的表达,进一步认识它们在瘢痕形成机制中的作用。方法:采用免疫组织化学技术(SABC法)检测了24例瘢痕患者病变组织,8例中孕胎儿皮肤及对照组正常组织中的CD44及HA的表达状况。结果:对HA/CD44的分析表明增生性瘢痕,成熟瘢痕与正常皮肤有显著性差异(P<0.05),胎儿皮肤与瘢痕疙瘩,增生性瘢痕及成熟瘢痕;胎儿皮肤,瘢痕疙瘩与正常皮肤有极显著性差异(P<0.01)。结论:CD44和HA与瘢痕形成有密切的联系,HA高产生高代谢则瘢痕形成少,HA高产生低代谢尤其是在瘢痕组织改建期,导致HA过量的沉积,则产生瘢痕增多。HA在创面愈合中抑制瘢痕形成的生物学作用与其相对浓度(HA/CD44)成正相关关系。     

胎儿皮肤中透明质酸的分布

目的通过研究不同胎龄胎儿皮肤中透明质酸的分布,观察其变化规律,从而探讨其分布与无瘢痕愈合之间的关系,为临床上瘢痕的预防及治疗提供理论依据。方法自4所医院妇产科取3~8个月龄的引产胎儿32例,取颌面部、背部、腹部及大腿内侧4处皮肤,进行免疫组织化学染色,观察透明质酸在皮肤中的分布。结果3个月龄胎儿皮肤中表皮层透明质酸染色阳性,4、5个月龄胎儿皮肤表皮上层染色阳性,真皮染色弱阳性,6~8个月龄胎儿皮肤中透明质酸染色表皮为阴性,真皮层阳性,随胎儿成熟度的提高透明质酸分布发生了明显的变化。不同部位皮肤之间透明质酸分布无明显差别。结论透明质酸分布随胎龄增长由表皮层向真皮层转移,透明质酸分布与无瘢痕愈合之间可能存在一定联系。     

胎儿和成人皮肤及其创面愈合过程中碱性成纤维细胞生长因子的表达及意义

目的　探讨胎儿和成人皮肤及其创面愈合过程中碱性成纤维细胞生长因子 (b FGF)的表达及其意义。方法　将孕龄 2 0～ 2 4周胎儿皮肤移植至 BAL B/ C裸鼠背部皮下 ,皮片成活后制造创面 ,建立胎儿无瘢痕愈合动物模型 ,定期获取相应标本。对临床所取正常成人皮肤及创面愈合皮肤标本 ,采用免疫组织化学染色方法 ,观察 b FGF的表达情况。　结果　正常胎儿皮肤及创伤后胎儿皮肤中均未见明显的 b FGF阳性表达。正常成人皮肤中血管周围可见阳性表达 ;创伤后成人皮肤也可见阳性表达 ,尤其成纤维细胞和血管内皮细胞创伤后表达明显增强。高倍镜视野随机观察计数b FGF阳性表达细胞数 ,正常胎儿皮肤为 2 .1± 0 .1,创伤后 12小时 ,1、3天和 1周胎儿皮肤分别为 2 .2± 0 .1、2 .1± 0 .3、2 .1± 0 .3和 2 .0± 0 .1;正常成人皮肤为 2 3.2± 4 .2 ,创伤后成人皮肤为 4 0 .5± 3.6 ,胎儿正常皮肤和创伤皮肤 b FGF表达与正常成人皮肤和创伤后皮肤 b FGF表达比较 ,差异有统计学意义 (P<0 .0 1)。　结论　 b FGF的阴性表达可能是胎儿皮肤无瘢痕愈合的重要原因之一。     

CD44及其配体HA在瘢痕与胎儿皮肤表达的相关进展

皮肤是人体最大的器官，受到一定程度的损害后，瘢痕形成是创面愈合的必然结果，但过度修复产生的增生性瘢痕，常常破坏人体表面的完整性或伴有各种程度的功能障碍，无瘢痕愈合则是人类组织修复最理想的结果。与成人皮肤创伤后形成瘢痕不同的是胎儿皮肤具有无瘢痕愈合特点，从而使对胎儿皮肤无瘢痕愈合的研究成为重点。CD４４和透明质酸（HA）作为蛋白分子，被认为在胚胎的形成、正常组织的维持、伤口愈合等方面具有重要作用。近年来，随着胎儿外科研究的逐步深入，HA在伤口愈合中的作用倍受关注。１胎儿皮肤无瘢痕愈合１９７１年，Burri…     

树突状细胞与Foxp3+细胞在瘢痕疙瘩中的免疫调节作用

目的 探讨树突状细胞与Foxp3+细胞(T调节细胞,regulatory T cell,Treg)在瘢痕疙瘩发病机制中的相互关系和免疫调节作用.方法 应用磁珠分离、流式细胞术和ELISA法检测瘢痕疙瘩患者(K组,15例)和正常人(N组,15例)外周血中Foxp3+细胞和成熟树突状细胞表面分子MHCII、CD83的表达和功能,分离外周血中树突状细胞分别与CD44 CD25-细胞共培养,测定Foxp3+细胞生成和IL-10的表达.结果 ①K组Foxp3+细胞占CD4+CD25+细胞的(1.45±0.22)%,细胞培养上清中IL-10的浓度为(一),明显低于N组[(5.63±0.95)%,(137±12)ng/L],P<0.05;②K组MHCⅡ+CD83+细胞占(85.47±4.13)%,培养上清中IL-12 p70的浓度为(263±21)ng/L,明显高于N组[(12.79±6.84)%,(一)],P<0.05;③K组DC与CD4+CD25-细胞共培养,3 d后诱导的Foxp3+细胞占CD4+细胞的(0.27±0.18)%,分泌的IL-10浓度为(一),明显低于N组DC与CD4+CD25-细胞共培养诱导的Foxp3+细胞含量和IL-10浓度[(2.53±0.72)%,(79.6±3.24)ng/L],P<0.05.结论 ①外周血中Foxp3+细胞的表达减少,功能降低提示瘢痕疙瘩患者可能存在外周的主动免疫抑制功能减弱;②瘢痕疙瘩患者中树突状细胞与Foxp3+细胞之间存在免疫调节作用;③Foxp3+细胞与瘢痕疙瘩的发病关系密切.     

胎儿和出生后机体皮肤内表皮生长因子和两种原癌基因表达变化及其与胎儿无瘢愈合的关系

胎儿皮肤创面愈合后一般不形成瘢痕,而成人创面愈合常有瘢修复,这一变化的机制目前尚不清楚.在研究中人们发现胎儿无瘢痕愈合不受胎儿所处的无菌、湿润和低氧环境的影响,而可能与伤口处的细胞因子浓度变化密切相关.表皮生长因子(epidermal growth factor,EGF)作为主要的修复生长因子,对创面愈合的多个环节都产生作用.EGFR是一种跨膜酪氨酸激酶受体,与EGF特异性结合后,通过MAPK信号通路,上调c-fos和c-myc等转录因子的基因表达后,诱导细胞核内特异性基因转录,刺激组织修复细胞增殖,趋化炎性细胞,表皮细胞和成纤维细胞向伤口聚集,加速创面愈合.目前,关于EGF,EGFR及其下游信号分子在人不同发育阶段的皮肤组织中的基因表达变化特征还缺乏研究,对这一规律的揭示,将有利于深入了解EGF调节创面愈合的机制和早期妊娠胎儿皮肤创面无瘢痕愈合的部分奥秘.用病理学技术检测不同发育阶段皮肤的结构特征后,提取18例不同胎龄(13～32周)的胎儿皮肤和6例出生后机体皮肤组织的总RNA,分离mRNA,用R-PCR方法检测这4种基因在不同组织中的表达变化规律.结果显示,在早期妊娠胎儿的皮肤中,EGF,EGFR,c-fos和c-myc基因表达较弱,随着胎儿的生长和发育,皮肤组织内这三种基因表达逐渐增强,在出生后机体的皮肤组织中,EGF,EGFR,c-fos和c-myc基因表达进一步升高,基因表达量分别为晚期妊娠胎儿皮肤的1.24倍,1.11倍,1.28倍和1.63倍.EGF、EGFR及其下游信号分子c-fos和c-myc基因在不同发育阶段的人皮肤组织内都有表达,显示EGF与其受体结合后引起的信号通路可能对皮肤的发生、结构功能的维持以及伤后修复十分重要.这4种基因在早期妊娠胎儿皮肤中低表达可能与胎儿皮肤创面无瘢痕修复密切相关.     

含FGL活性片段的自组装多肽支架材料修复大鼠脊髓损伤的研究

目的 建立大鼠脊髓损伤模型,将含FGL功能化多肽自组装神经支架材料(FGL-NS)植入到脊髓损伤局部,探讨FGL-NS神经支架材料修复脊髓损伤的效果和机制.方法 麻醉大鼠后,暴露胸10水平脊髓,用特制血管夹(夹力24g)钳夹1 min,建立大鼠胸髓钳夹损伤模型.设立空白组、对照组和实验组,分别于损伤后24h,暴露脊髓损伤局部,将2.5μl等渗葡萄糖溶液、1％ RADA-16和1％ FGL-NS多肽溶液注射入损伤局部.术后3d、1、3、5、7和9周分别采用Basso-Beattie-Bresnahan(BBB)评分评估大鼠脊髓损伤经治疗后运动功能恢复情况,术后9周取脊髓损伤部位组织,行半胱氨酰天冬氨酸特异性蛋白酶(Caspase)-3、神经丝蛋白-200 (NF-200)和胶质纤维酸性蛋白(GFAP)免疫组织化学染色评估损伤部位细胞凋亡、轴突再生和瘢痕形成情况.结果 成功建立大鼠胸髓钳夹损伤模型.BBB运动学评分大鼠脊髓损伤后经FGL-NS材料治疗后,BBB评分随时间逐渐升高,自伤后第5周起,显著高于RADA-16治疗组和空白组,大鼠运动功能显著改善.免疫组织化学染色结果显示,损伤后第9周,FGL-NS治疗组脊髓损伤局部可见大量NF-200阳性的神经元细胞[(35.32±3.12)个/视野],显著高于RADA-16组[(18.56±2.64)个/视野]和空白组[(14.83±1.43)个/视野],Caspase-3阳性的凋亡细胞[(22.45 ±2.74)个/视野]显著少于RADA-16组[(30.86 ±3.75)个/视野],而且损伤区GFAP染色的积分吸光度(IA)值为0.50±0.02,明显小于对照组(1.30 ±0.09)和空白组(1.60±0.11).结论 功能化多肽自组装神经支架材料FGL-NS能促进脊髓损伤大鼠的运动功能恢复,能减少脊髓损伤部位细胞凋亡,促进神经元再生,并减少胶质瘢痕形成.     

不同发育时期胎儿皮肤中基质金属蛋白酶-9,2及金属蛋白酶-2抑制因子基因表达的变化

目的:研究基质金属蛋白酶-9(MMP-9)、基质金属蛋白酶-2(MMP-2)及其组织抑制因子(TIMP-2)在不同胎龄的胎儿皮肤中表达的变化特征及其可能的生物学意义.方法:用病理学技术检测不同发育时期胎儿皮肤的结构特征后,提取18例不同胎龄(13～33周)的胎儿皮肤总RNA后,分离mRNA,用RT-PCR方法检测这3种基因在不同组织中的表达变化规律.结果:MMP-9、MMP-2和TIMP-2基因在不同发育时期的胎儿皮肤组织中的表达变化规律相似.在早期妊娠胎儿皮肤中,这3种基因表达较弱,随着胎儿生长发育,MMP-9,MMp-2和TIMP-2基因表达逐渐增强,妊娠晚期的皮肤组织内,这3种基因表达产物的灰密度比值分别是妊娠早期的8.8、2.4和3.1倍,基因表达水平显著升高(P＜0.05).结论:MMP-9,2和TIMP-2对皮肤的生长发育、结构功能的维持以及创面修复具有重要的调节作用.妊娠早期,TIMP-2基因低表达可能与胎儿皮肤创面无瘢痕愈合相关,而妊娠晚期皮肤中TIMP-2基因表达增强可能是创面愈合后形成瘢痕的机制之一.     

Cyclin A和p21cip1在增生性瘢痕成纤维细胞中的表达及与细胞周期相关性的探讨

目的 探讨增生性瘢痕(HS)不同时期成纤维细胞(FB)中细胞周期素A(Cyclin A)、细胞周期蛋白-激酶的抑制因子p21cip1基因及蛋白的表达与同时期FB所处的细胞周期的相关性,为细胞周期相关基因的干预用于HS的防治提供前期理论依据.方法 采集HS不同时段(3、6、12、24个月)瘢痕标本32例,每个时段8例,并以8例正常皮肤作为对照组.利用实时荧光定量PCR法、蛋白质免疫印迹(Western blotting)法检测HS及正常皮肤中Cyclin A和p21cip1的mRNA、蛋白表达水平;用流式细胞术检测HS中FB的细胞周期情况.结果 HS中CyclinA的mRNA及蛋白质表达量在3、6、12、24个月组分别为19.34±2.41、0.99±0.11,19.30±1.42、0.96±0.09,10.73±2.93、0.66±0.58,9.29±0.97、0.65±0.14.p21cip1的mRNA及蛋白质表达量在3、6、12、24个月组分别为2.8±0.69、0.35±0.07;4.95±1.82、0.44±0.07;9.98±1.19、0.56±0.06;10.25±1.46、0.59±0.06.Cyclin A的mRNA和蛋白的表达,3与6个月组比较差异无统计学意义(P>0.05);3、6个月组分别与12、24个月和正常组比较差异有统计学意义(P<0.05);12、24个月与正常组比较差异无统计学意义(P>0.05).p21cip1的mRNA和蛋白的表达,3个月组低于6个月组(P<0.05);3、6个月组分别与12、24个月和正常组比较表达明显降低(P<0.05);12、24个月和正常组比较差异无统计学意义(P>0.05).流式细胞仪检测结果显示3、6个月增生性瘢痕中细胞主要分布在S、G2/M期;而12、24个月组增生性瘢痕及正常皮肤中的细胞多处于G0/G1期.结论 随着HS的发展,HS中CyclinA的mRNA和蛋白的表达强度呈由强至弱的变化,p21cip1的mRNA和蛋白的表达则呈由弱至强的变化.不同时期HS中CyclinA和p21cip1各自的mRNA和蛋白的表达趋势基本一致;不同时期HS中FB的细胞周期分布情况与CyclinA和p21cip1 mRNA和蛋白表达强弱相对应;在HS发生早期对这两个基因进行干预,有可能在控制增生性瘢痕的发生和发展中发挥作用.     

胎儿及成人皮肤创面愈合过程中PDGF和EGF表达的对比性研究

目的 探讨人胎儿和成人皮肤及其创面愈合过程中PDGF和EGF的表达及意义。方法 利用已建立的人胎儿无瘢痕愈合动物模型，获取相应标本，结合临床所取成人皮肤标本，采用免疫组化染色方法，观察PDGF，EGF的表达情况。结果 ①正常胎儿皮肤中未见明显的PDGF阳性染色；创伤后12h、1d的胎儿表皮及真皮浅层可见PDGF的弱阳性表达；创伤后3d、1周的胎儿皮肤中PDGF的表达呈阴性；正常成人皮肤可在成纤维细胞，巨噬细胞及毛细血管见到阳性表达；创伤后表达加强；②正常胎儿皮肤表皮全层和毛囊，皮脂腺及汗腺细胞可见EGF的阳性表达；创伤后的胎儿皮肤中EGF的表达未见到明显变化；正常成人皮肤可见表皮基底层有中度阳性表达，毛囊，汗腺细胞也可见到轻度表达，创伤后表达有所减弱。结论 生长因子在胎儿和成人皮肤创面愈合过程中的差异表达可能是胎儿无瘢痕愈合的重要原因之一。     

Healthy human second‐trimester fetal skin is deficient in leukocytes and associated homing chemokines

The lack of immune cells in mid‐gestational fetal skin is often mentioned as a key factor underlying scarless healing. However, the scarless healing ability is conserved until long after the immune system in the fetus is fully developed. Therefore, we studied human second‐trimester fetal skin and compared the numbers of immune cells and chemokine levels from fetal skin with adult skin. By using immunohistochemistry, we show that healthy fetal skin contains significant lower numbers of CD68⁺‐macrophages, Tryptase⁺‐mast cells, Langerin⁺‐Langerhans cells, CD1a⁺‐dendritic cells, and CD3⁺‐T cells compared to adult skin. Staining with an early lineage leukocyte marker, i.e., CD45, verified that the number of CD45⁺‐immune cells was indeed significantly lower in fetal skin but that sufficient numbers of immune cells were present in the fetal lymph node. No differences in the vascular network were observed between fetal and adult skin. Moreover, significant lower levels of lymphocyte chemokines CCL17, CCL21, and CCL27 were observed in fetal skin. However, levels of inflammatory interleukins such as IL‐6, IL‐8, and IL‐10 were undetectable and levels of CCL2 were similar in healthy fetal and adult skin. In conclusion, this study shows that second‐trimester fetal skin contains low levels of immune cells and leukocyte chemokines compared to adult skin. This immune cell deficiency includes CD45⁺ leukocytes, despite the abundant presence of these cells in the lymph node. The immune deficiency in healthy second‐trimester fetal skin may result in reduced inflammation during wound healing, and could underlie the scarless healing capacities of the fetal skin.     

Ontogeny of expression of basic fibroblast growth factor and its receptors in human fetal skin

The wounds in skin of early gestational fetus healwithout scar formation by a process resemblingregeneration rather than repair.1The ability torepair congenital anomalies in uterus such as cleft lipwith scarless healing will revolutionize the field ofreconstructive plastic surgery. Furthermore, if thebiological properties of scarless fetal healing aredetermined, these characteristics mightbe replicated inthe adult environment with tremendous clinicalbenefits. This non-scarring phenomenon is ge…     

Scarless human fetal skin repair is intrinsic to the fetal fibroblast and occurs in the absence of an inflammatory response

The fetus heals skin wounds without scar formation. Human fetal skin that is transplanted to a subcutaneous location on an adult athymic mouse and subsequently wounded heals without scar formation, whereas the same skin heals with scar formation when transplanted to a cutaneous location. In situ hybridization with species-specific DNA probes and immunohistochemistry were performed to characterize the healing process of human fetal skin in these two locations. Species-specific human and mouse DNA probes were constructed and used to probe graft wounds under high stringency in situ hybridization conditions. Immunostaining for species-specific fibroblasts, macrophages, and neutrophils was also performed. We found that the cutaneous human fetal grafts healed with scar and showed an influx of mouse fibroblasts and macrophages. In contrast, subcutaneous human fetal grafts showed exclusively human fetal fibroblasts in the wound environment, an absence of inflammatory cells, and scar-free repair. We conclude that the highly organized collagen deposition in scarless human fetal wound repair appears to be intrinsic to the human fetal fibroblasts and occurs in the absence of an adult-like inflammatory response.     

Wound healing in a fetal,adult, and scar tissue model: A comparative study

Early gestation fetal wounds heal without scar formation. Understanding the mechanism of this scarless healing may lead to new therapeutic strategies for improving adult wound healing. The aims of this study were to develop a human fetal wound model in which fetal healing can be studied and to compare this model with a human adult and scar tissue model. A burn wound (10 × 2 mm) was made in human ex vivo fetal, adult, and scar tissue under controlled and standardized conditions. Subsequently, the skin samples were cultured for 7, 14, and 21 days. Cells in the skin samples maintained their viability during the 21‐day culture period. Already after 7 days, a significantly higher median percentage of wound closure was achieved in the fetal skin model vs. the adult and scar tissue model (74% vs. 28 and 29%, respectively, p<0.05). After 21 days of culture, only fetal wounds were completely reepithelialized. Fibroblasts migrated into the wounded dermis of all three wound models during culture, but more fibroblasts were present earlier in the wound area of the fetal skin model. The fast reepithelialization and prompt presence of many fibroblasts in the fetal model suggest that rapid healing might play a role in scarless healing.     

Cells, matrix, growth factors, and the surgeon. The biology of scarless fetal wound repair.

OBJECTIVE: This review updates the surgeon about the cellular, matrix, and growth factor components of scarless fetal wound repair. SUMMARY BACKGROUND DATA: Fetal skin wound healing is characterized by the absence of scar tissue formation. This unique repair process is not dependent on the sterile, aqueous intrauterine environment. The differences between fetal and adult skin wound healing appear to reflect processes intrinsic to fetal tissue, such as the unique fetal fibroblasts, a more rapid and ordered deposition and turnover of tissue components, and, particularly, a markedly reduced inflammatory infiltrate and cytokine profile. Scarless fetal wounds are relatively deficient in the inflammatory cytokine, transforming growth factor beta (TGF-beta). In contrast, the fibrosis characteristic of adult wound repair may be associated with TGF-beta excess. Recent experimental studies suggest that specific anti-TGF-beta therapeutic strategies can ameliorate scar formation in adult wound repair and fibrotic diseases. Inhibitors of TGF-beta may be important future drugs to control scar. CONCLUSIONS: Based on the scarless fetal wound repair model, a number of ways in which the matrix and cellular response of the healing adult wound might be manipulated to reduce scarring are reviewed.     

The ontogeny of scarless healing II: EGF and PDGF-B gene expression in fetal rat skin and fibroblasts as a function of gestational age

Twenty years ago, surgeons noted the ability of early-gestation fetal skin to heal in a scarless manner. Since that time, numerous investigators have attempted to elucidate the mechanisms behind this phenomenon. As a result of this effort, it is now well established that many animals undergo a transition late in development from scarless cutaneous healing to a scar-forming, adultlike phenotype. The authors have been interested in the role played by cytokines known to be involved in the adult wound-healing process and how they relate to scarless repair. They therefore asked the following question: Are genes for epidermal growth factor (EGF) and platelet-derived growth factor-B (PDGF-B) expressed differentially as a function of gestational age in fetal rat skin and dermal fibroblasts? To answer this question, skin from fetal Sprague-Dawley rats (N = 56) at time points that represented both the scarless and scar-forming periods of rat gestation was harvested. In addition, fibroblasts derived from fetal rat skin were cultured in vitro at similar times. These cells were expanded in culture and, when confluent, total ribonucleic acid from both fibroblasts and whole skin was extracted and subjected to Northern blot analysis with probes for EGF and PDGF-B. Results demonstrated that neither EGF nor PDGF-B gene expression changed markedly as a function of gestational age in fetal fibroblasts alone. In whole skin, however, both EGF and PDGF-B demonstrated a marked decrease in gene expression with increasing gestational age. Furthermore, the most striking decrease in gene expression for both cytokines came between 16 and 18 days of gestation-the transition point between scarless and scar-forming repair in the fetal rat. These data suggest that EGF and PDGF may play a role in the mechanism of scarless cutaneous repair. Moreover, it appears that fetal fibroblasts are not the cell type responsible for this differential gene expression. These results raise questions about the unique cytokine milieu likely to be present during the time of scarless healing and the cells that ultimately guide the mechanisms leading to skin regeneration.     

一氧化氮在成兔与胚胎兔创面愈合过程中含量的比较

目的 :分析胚胎无瘢痕愈合的潜在原因 ,研究NO(一氧化氮 )在成人型和胚胎型愈合过程中的差别。方法 :在已建立的胎兔创伤模型的基础上 ,用一氧化氮酶法试剂盒检测胚胎兔和成兔皮肤匀浆液中NO的含量 ,并对结果进行比较。结果 :①正常胎兔不同孕期皮肤中NO含量无差别。②正常胎兔皮肤中NO含量高于正常成兔皮肤中NO含量 (P <0 .0 1)。③创伤胎兔皮肤中NO含量高于正常胎兔皮肤中NO含量 (P <0 .0 1)。④创伤成兔皮肤中NO含量高于正常成兔皮肤中NO含量 (P <0 .0 1)。⑤创伤胎兔皮肤中NO含量高于创伤成兔皮肤中NO含量 (P <0 .0 1)。结论 :NO参与了胚胎和成年动物的创面愈合过程 ,并在两种愈合过程中存在差别