干扰素α-2b对瘢痕疙瘩成纤维细胞凋亡及端粒酶活性的影响

目的 观察干扰素α-2b（IFNα-2b）对瘢痕疙瘩成纤维细胞生长增殖、端粒酶活性及凋亡的影响，探讨其在瘢痕疙瘩治疗中的作用机制。方法 进行成纤维细胞原代培养，细胞分别来自8例瘢痕疙瘩标本和8例正常皮肤标本。第3到4代的细胞用于实验。以干扰素α-2b作用于体外培养的瘢痕疙瘩和正常皮肤成纤维细胞，噻唑蓝（MTF）法检测成纤维细胞生长增殖情况，聚合酶链反应-酶联免疫吸附法（PCR-ELISA法）检测不同时间成纤维细胞端粒酶活性，应用流式细胞仪观察处理后成纤维细胞凋亡。结果 IFNα-2b对瘢痕疙瘩和正常皮肤成纤维细胞有生长抑制作用，可明显下调成纤维细胞端粒酶活性，和对照组比较差异有统计学意义（P〈0．05），并呈现出明显的时间-效应关系。体外培养的瘢痕疙瘩和正常皮肤成纤维细胞经10000U／ml IFNα-2b处理后，能诱导成纤维细胞凋亡发生，与对照组比较差异有统计学意义（P〈0．01），且具有明显的时间依赖性。结论 作为一个负性调节因子，IFNα-2b能抑制瘢痕疙瘩成纤维细胞的生长增殖并诱导成纤维细胞发生凋亡，降低成纤维细胞端粒酶活性是其作用机制之一。     

α-2b干扰素对瘢痕疙瘩成纤维细胞凋亡及端粒酶逆转录酶、bcl-2 mRNA表达的影响

目的 观察α-2b干扰素(IFNα-2b)对瘢痕疙瘩成纤维细胞生长增殖、凋亡及端粒酶逆转录酶(hTERT)、bcl-2 mRNA表达的影响,探讨其在瘢痕疙瘩治疗中的作用机制.方法 进行成纤维细胞原代培养,细胞分别来自8例瘢痕疙瘩标本和8例正常皮肤标本.第3～4代的细胞用于实验.以IFNa-2b作用于体外培养的瘢痕疙瘩和正常皮肤成纤维细胞,MTT法检测成纤维细胞生长增殖情况,应用流式细胞仪观察处理后成纤维细胞凋亡,RT-PCR法检测成纤维细胞hTERT和bcl-2mRNA的表达.结果 IFNα-2b对瘢痕疙瘩和正常皮肤成纤维细胞生长有抑制作用,体外培养的瘢痕疙瘩和正常皮肤成纤维细胞经10 000 U/ml IFNα-2b处理后,能诱导成纤维细胞凋亡发生,RT-PCR检测hTERT和bcb2 mRNA表达降低,和对照组相比,差异有统计学意义(P<0.01),且具有明显的时间依赖性.结论 作为一个负性调节因子,IFNα-2b能抑制瘢痕疙瘩成纤维细胞的生长增殖并诱导成纤维细胞发生调亡,下调成纤维细胞端粒酶活性是其重要作用机制之一.通过抑制端粒酶活性进行抗瘢痕疙瘩治疗可能是一个新途径.     

干扰素α-2b对瘢痕成纤维细胞凋亡的影响

目的:探讨干扰素α-2b对瘢痕成纤维细胞(fibroblasts cell FB)凋亡的影响。方法:利用免疫组织化学和原位杂交方法检测瘢痕疙瘩、增生性瘢痕、正常皮肤体外培养FB的Bax和Bcl-2蛋白以及DNA的变化。结果:瘢痕疙瘩FB的Bcl-2蛋白表达量减少(P<0.05),瘢痕疙瘩FB的Bax、增生性瘢痕及正常皮肤FB Bax和Bcl-2蛋白表达无显著性变化(P>0.05)。三者FB Bax/Bcl-2b比值无明显差异(P>0.05),DNA检测三者FB未见典型的细胞凋亡的梯形条带。结论:干扰素α-2b不能诱导瘢痕疙瘩和增生性瘢痛FB细胞凋亡。     

曲安奈德、干扰素α-2b和维拉帕米治疗增殖瘢痕的作用机制比较

目的 比较曲安奈德、干扰素α-2b和维拉帕米局部注射对瘢痕疙瘩和增生性瘢痕增殖、凋亡和TGF-β1表达的影响. 方法 增生性瘢痕和瘢痕疙瘩各6例,局部注射曲安奈德(40 mg/ml)、干扰素α-2b(150万U/ml)和维拉帕米(2.5 mg/ml)后7 d,切取标本,采用免疫组织化学、末端脱氧核苷酸介导的生物素化的脱氧尿嘧啶DNA切口末端标记方法,检测细胞增殖核抗原和TGF-β1的表达及细胞发生的凋亡情况,并以未注射药物的瘢痕疙瘩和增生性瘢痕以及健康皮肤为对照. 结果 ①曲安奈德可抑制瘢痕疙瘩和增生性瘢痕细胞增殖和诱导细胞凋亡,同时抑制细胞TGF-β1表达从而抑制瘢痕的增殖增生;②干扰素α-2b可通过抑制瘢痕疙瘩、增生性瘢痕细胞的增殖和TGF-β1表达而抑制瘢痕的增殖增生,但其不能诱导细胞凋亡;③维拉帕米可通过抑制瘢痕疙瘩、增生性瘢痕细胞的增殖和诱导细胞凋亡而抑制瘢痕的增殖,同时抑制细胞TGF-β1表达,其诱导细胞凋亡的作用妹强于曲安奈德,但抑制TGF-β1表达作用弱于曲安奈德和干扰素α-2b. 结论 曲安奈德、干扰素α-2b和维拉帕米局部注射后,对瘢痕疙瘩和增生性瘢痕在临床上虽均有效,但作用机制不尽相同.     

异常瘢痕成纤维细胞在低血清及白介素1β作用下的细胞凋亡研究

目的 明确低血清及白介素1β（IL-1β）对瘢痕疙瘩,增生性瘢痕及正常皮肤成纤维细胞诱导细胞凋亡的作用。方法 对6例瘢痕疙瘩、6例增生性瘢痕及6例正常皮肤标本采用细胞培养、免疫组织化学及凝胶电泳方法,通过检测Bax,Bcl-2蛋白及特异性DNA梯形条带,对不同成纤维细胞在低血清中及IL-1β作用后的细胞凋亡进行了研究。结果 （1）在低血清中,瘢痕疙瘩和增生性瘢痕成纤维细胞的Gax/Bcl-2蛋白表达比值没有明显改变,但增生性瘢痕成纤维细胞出现程度较轻的细胞凋亡,而瘢痕疙瘩成纤维细胞未见明显细胞凋亡;正常皮肤成纤维细胞出现细胞凋亡,且Bax/Bcl-2比值升高,表明发生细胞凋亡,（2）IL-1β作用下,三者成纤维细胞均发生凋亡,瘢痕疙瘩和增生性瘢痕凋亡比正常皮肤严重。但Bax/Bcl-2比值在瘢痕疙瘩升高,在正常皮肤降低。增生性瘢痕无明显变化。结论 不同的成纤维细胞特性存在差异。     

异常瘢痕成纤维细胞在低血清及白介素1_β作用下的细胞凋亡研究

目的　明确低血清及白介素 1β(IL - 1β)对瘢痕疙瘩、增生性瘢痕及正常皮肤成纤维细胞诱导细胞凋亡的作用。方法　对 6例瘢痕疙瘩、6例增生性瘢痕及 6例正常皮肤标本采用细胞培养、免疫组织化学及凝胶电泳方法 ,通过检测Bax、Bcl 2蛋白及特异性DNA梯形条带 ,对不同成纤维细胞在低血清中及IL 1β作用后的细胞凋亡进行了研究。结果　①在低血清中 ,瘢痕疙瘩和增生性瘢痕成纤维细胞的Bax Bcl 2蛋白表达比值没有明显改变 ,但增生性瘢痕成纤维细胞出现程度较轻的细胞凋亡 ,而瘢痕疙瘩成纤维细胞未见明显细胞凋亡 ;正常皮肤成纤维细胞出现细胞凋亡 ,且Bax Bcl 2比值升高 ,表明发生细胞凋亡。②IL 1β作用下 ,三者成纤维细胞均发生凋亡 ,瘢痕疙瘩和增生性瘢痕凋亡比正常皮肤严重 ,但Bax Bcl 2比值在瘢痕疙瘩升高 ,在正常皮肤降低 ,增生性瘢痕无明显变化。结论　不同的成纤维细胞特性存在差异。     

激素和干扰素对瘢痕疙瘩成纤维细胞生长影响的研究

为了解氢化可的松和干扰素α－２ｂ对瘢痕疙瘩浸润、增生和老化各部分成纤维细胞的影响是否相同，对６例瘢痕疙瘩不同部位和６例正常皮肤成纤维细胞在培养基中加入氢化可的松（０．１ｍｇ／ｍｌ和０．５ｍｇ／ｍｌ）及干扰素α－２ｂ（１０００μ／ｍｌ）后的增殖情况作了初步研究。结果：氢化可的松浓度为０．１ｍｇ／ｍｌ时，所有细胞均被抑制；当氢化可的松浓度升至０．５ｍｇ／ｍｌ时，几乎所有的细胞均不能存活。干扰素α－２ｂ对瘢痕疙瘩各部分成纤维细胞及正常皮肤的成纤维细胞反应略有不同，瘢痕疙瘩老化部的成纤维细胞不受影响，而其它细胞均被抑制。提示瘢痕疙瘩老化部成纤维细胞对干扰素α－２ｂ的敏感性与其它成纤维细胞存在差异。     

激素治疗瘢痕的机理研究

目的　明确类固醇治疗瘢痕的具体作用机理。　方法　用细胞培养、免疫组织化学及分子生物学技术对 6例瘢痕疙瘩 ,6例增生性瘢痕患者及 6例正常人皮肤的成纤维细胞在激素作用下的细胞凋亡进行了研究 ;同时对 6例激素局部注射后的在体增生性瘢痕的成纤维细胞的增殖、生物合成及细胞凋亡进行了研究。　结果　 (1)激素可以诱导体外培养的不同成纤维细胞的凋亡 ,同时伴有Bax/Bcl 2蛋白比率的升高。 (2 )局部注射激素可以通过抑制PDGF基因表达而抑制瘢痕成纤维细胞的在体增殖。 (3)局部注射激素可以通过抑制转录而抑制前胶原基因表达从而抑制在体瘢痕成纤维细胞的I、III型胶原合成。 (4)激素局部注射可引起瘢痕c myc和p5 3基因表达增高从而诱导在体瘢痕的细胞凋亡。　结论　激素治疗瘢痕的疗效是通过抑制增殖及生物合成促进细胞凋亡而实现的。     

细胞外信号调节激酶及应激活化蛋白激酶通路蛋白在瘢痕疙瘩成纤维细胞中的表达

目的通过比较瘢痕疙瘩及正常皮肤中细胞外信号调节激酶(extracellular signal-regulated kinase,ERK)、应激活化蛋白激酶(c-Jun amino-terminal kinase,JNK)信号通路的表达,探讨其在瘢痕疙瘩形成中的作用。方法取四川大学华西医院烧伤整形科收治的26例患者皮肤组织,其中行瘢痕疙瘩切除患者(实验组)16例,瘢痕疙瘩形成时间8个月～10年;胸部6例,耳垂4例,会阴部2例,肩部3例,腹部1例;均经病理检查确诊为瘢痕疙瘩。10例整形手术患者自愿捐赠的正常皮肤作为对照组,腹部4例,大腿3例,肩部2例,背部1例。取标本采用Envision二步法行免疫组织化学染色,观察磷酸化及非磷酸化JNK和ERK表达情况,并采用Image Pro Plus 4.5图像分析系统测定积分吸光度(IA)值,观察阳性染色强度。结果免疫组织化学染色观察显示,对照组正常皮肤成纤维细胞中未见明显的磷酸化及非磷酸化ERK、JNK阳性表达;而实验组主要在成纤维细胞中表达,阳性颗粒主要位于细胞质和细胞核内。实验组磷酸化ERK及JNK的IA值明显高于对照组(P<0.05),非磷酸化ERK及JNK两组间差异无统计学意义(P>0.05)。结论磷酸化JNK、ERK信号通路蛋白在瘢痕疙瘩中异常高表达,提示该通路可能与瘢痕疙瘩形成密切相关。     

甲基化酶抑制剂5-氮杂-2-脱氧胞苷对瘢痕疙瘩成纤维细胞TGF-β/smad信号通路的影响

目的 探讨甲基化酶抑制剂5-氮杂-2-脱氧胞苷对瘢痕疙瘩成纤维细胞TGF-β/smad信号通路的影响.方法 收集瘢痕疙瘩及正常皮肤组织各15例,免疫组化检测磷酸化smad2(p-smad2)和磷酸化smad3(p-smad3)在瘢痕疙瘩和正常皮肤中的阳性表达率;将瘢痕疙瘩分为实验组和对照组,实验组以5-氮杂-2-脱氧胞苷(5×10-5mmol/L)干预,对照组用等量的DMEM培养液,采用组织块法培养人瘢痕疙瘩成纤维细胞,流式细胞仪分析5-氮杂-2-脱氧胞苷(5×10-5mol/L)对瘢痕疙瘩成纤维细胞周期及凋亡的影响;Western blot检测各组p-smad2、p-smad3、TGF-β1和smad7的表达变化;细胞免疫荧光染色法观察各组瘢痕疙瘩成纤维细胞内p-smad2和p-smad3蛋白的影响.结果 瘢痕疙瘩组织中p-smad2和p-smad3阳性表达率明显高于正常皮肤组织中p-smad2和p-smad3阳性表达.流式细胞仪显示5-氮杂-2-脱氧胞苷干预瘢痕疙瘩成纤维细胞后,细胞停滞于G0/G1期比例增加并且细胞凋亡率增加,瘢痕疙瘩成纤维细胞中p-smad2和p-smad3蛋白的表达减少,同时,TGF-β1蛋白表达减少,smad7蛋白表达回升.此外,5-氮杂-2-脱氧胞苷抑制smad2和smad3磷酸化及核转移.结论 甲基化酶抑制剂5-氮杂-2-脱氧胞苷可抑制瘢痕疙瘩成纤维细胞的增殖及促进其凋亡,其作用机制可能与抑制TGF-β/smad信号通路有关.     

Effects of steroids,interferon-2B,or interluekin 1B on apoptosis of fibroblasts from keloid,hypertrophic scars,and normal skin and related signal pathway

Wound healing can lead to hypertrophic scar or keloid formation, characterized by an overabundant extracellular matrix. Current established treatment strategies include surgical resection, triamcinolone steroid injection, pressure therapy, silicone therapy, radiotherapy, etc. Cytokines also play a critical role in the regulation of cellular activities and extracellular matrix metabolism. Interferons (IFN) represent a group of antifibroproliferative agents that inhibit fibroblast proliferation and collagen production, and interleukin (IL)-1β also accelerates hypertrophic scar fibroblasts to produce collagenolytic enzymes, leading to tissue destruction. This study addressed the effects of steroid, IFN α-2b, or IL-1β on apoptosis and cell pathway of fibroblasts from keloids, hypertrophic scars, and normal skins and different responses of different fibroblasts. Six samples of keloid, six samples of hypertrophic scar, and six samples of normal skin were, respectively, collected from patients, and fibroblasts from different sources were cultured in vitro. After different fibroblasts were treated with dexamethasone (0.1 mg/ml) or IFN α-2b (1,000 μ/ml) or IL-1β (200 μ/ml), Bax and Bcl-2 were detected in situ by immunohistochemical staining; deoxyribonucleic acid ladders of different fibroblasts were observed by gel electrophoresis, and relative activated (phospho-) extracellular-signal-regulated kinase (ERK) 1/2 and c-Jun N-terminal kinase (JNK) pathways were detected by the method of fast activated cell-based enzyme-linked immunosorbent assay. In media containing dexamethasone, apoptosis took place in fibroblasts from keloids, hypertrophic scars, and normal skins by gel electrophoresis with increased rate of Bax/Bcl-2. Activated (phospho-) ERK1/2 and activated (phospho-) JNK expressions increased in three different fibroblasts. In media containing IFN α-2b, no apoptosis took place in three different fibroblasts without any change of expressions of Bax and Bcl-2 except for the expression of decreased Bcl-2 in fibroblasts from keloids. Activated (phospho-) ERK1/2 expression decreased in fibroblasts from keloid and hypertrophic scars without any changes of activated (phospho-) JNK expression, and IFN α-2b did not affect both activated (phospho-) ERK1/2 and activated (phospho-) JNK expressions in fibroblasts from normal skin. In media containing IL-1β, apoptosis of fibroblasts from keloids was induced by stimulating activated (phospho-) ERK1/2 and activated (phospho-) JNK pathways; IL-1β could not induce apoptosis of fibroblasts from normal skin (radio of Bax/Bcl-2 decreasing) whose activated (phospho-) ERK1/2 pathway was stimulated without any changes of activated (phospho-) JNK expression. Apoptosis in fibroblasts from hypertrophic scars was induced by activating the JNK pathway and prohibiting the ERK1/2 pathway. The effects of steroid, IFN α-2b, or IL-1β on apoptosis of different fibroblasts were different through different cell signal pathways, although all of them were effective for treatment of abnormal scars.     

增殖瘢痕成纤维细胞接触后增殖及生物合成特性对异常瘢痕形成的机理

目的 为明确不同异常瘢痕成纤维细胞在体外完全接触后其增殖活性及生物全成功能的特性。方法 以瘢痕疙瘩、增生性瘢痕和正常皮肤（各6例）为材料，通过细胞培养、免疫组织化学及分子生物学等方法，对不同成纤维细胞在细胞接触及未接触时通过检测增殖细胞核内抗原、P16、Ⅰ、Ⅲ型胶原蛋白及前胶原基因表达对成纤维细胞的增殖、抑制及生物合成进行了研究。结果 瘢痕疙瘩成纤维细胞接触表现为细胞交叉重叠及较高的增殖活性及旺盛的生物合成功能，提示其失去了接触性抑制及密度抑制。皮肤成纤维细胞接触后则增殖及生物合成功能明显下降。增生性瘢痕成纤维细胞接触后表现为旺盛的生物合成功能，但其增殖活性处于瘢痕疙瘩和正常皮肤成纤维细胞之间。结论 不同瘢痕成纤维细胞接触后增殖及生物合成的特性可能是形成不同瘢痕的机理之一。     

FBXL6 is dysregulated in keloids and promotes keloid fibroblast growth by inducing c-Myc expression

C-MYC-mediated keloid fibroblasts proliferation and collagen deposit may contribute to the development of keloids. F-box and leucine-rich repeat protein 6 (FBXL6) is reported to be involved in tumour progression, while the role of FBXL6 in keloid fibroblasts is not deciphered. Normal control skins, hypertrophic scars and keloid tissues were collected and prepared for FBXL6 detection. FBXL6 short hairpin RNAs (shRNAs) or FBXL6 over-expression plasmids were transfected into keloid fibroblasts, and then c-MYC plasmids were further transfected. Cell viability was assayed with a Cell-Counting Kit-8 kit. The relative expression of FBXL6, Cyclin A1, Cyclin D2, Cyclin E1 and Collagen I was detected with real-time PCR and Western blot. Elevated FBXL6 expression could be observed in keloid tissues and hypertrophic scars. FBXL6 shRNAs transfection could inhibit the viability of keloid fibroblasts with diminished c-MYC expression and down-regulated Cyclin A1, Cyclin D2, Cyclin E1 and Collagen I expression. At the same time, overexpressed FBXL6 could promote the proliferation of keloid fibroblasts. Overexpression of c-MYC could promote the proliferation of keloid fibroblasts reduced by FBXL6 shRNAs with up-regulated Cyclin A1 and Collagen I expression. FBXL6 could promote the growth of keloid fibroblasts by inducing c-MYC expression, which could be targeted in keloids treatment.     

瘢痕中肌动蛋白及肌球蛋白的实验研究

目的　探讨增生性瘢痕、瘢痕疙瘩及正常皮肤成纤维细胞中肌动蛋白和肌球蛋白Ⅱ的不同表达情况及其与瘢痕挛缩的关系。方法　取增生性瘢痕15例,瘢痕疙瘩10例,正常皮肤15例,用免疫组织化学方法检测其中肌动蛋白和肌球蛋白Ⅱ的表达情况,同时做细胞培养,用流式细胞术检测成纤维细胞中肌动蛋白和肌球蛋白Ⅱ的表达情况。结果　增生性瘢痕肌球蛋白Ⅱ的免疫组织化学染色呈阳性,而瘢痕疙瘩及正常皮肤肌球蛋白Ⅱ的表达均为阴性。增生性瘢痕肌球蛋白Ⅱ的表达较其它两种组织有非常显著性差异(P<0.01),而瘢痕疙瘩和正常皮肤无显著性差异(P>0.05)。流式细胞术检测增生性瘢痕、瘢痕疙瘩及正常皮肤三种组织中肌球蛋白Ⅱ的阳性率分别为(95.11±2.78)%、(16.86±7.11)%及(5.31±1.79)%,增生性瘢痕肌球蛋白Ⅱ表达的阳性率较其它两种组织有非常显著性差异(P<0.01),而瘢痕疙瘩和正常皮肤无显著性差异(P>0.05)。三种组织中肌动蛋白的免疫组织化学染色均为阳性,无显著性差异(P>0.05)。流式细胞术检测三种组织中肌动蛋白的阳性率分别为(77.77±15.43)%、(88.89±10.29)%及(82.92±13.48)%,其表达的阳性率无显著性差异(P>0.05)。结论　瘢痕挛缩与肌球蛋白Ⅱ密切相关,而肌动蛋白在细胞中除作为细胞的收缩蛋白之一外,同时与细胞的活动及运动有关,是细胞生命活动中必不可少的蛋白之一。     

Phosphorylation of extracellular signal-regulated protein kinase in cultured keloid fibroblasts when stimulated by platelet-derived growth factor BB.

Abnormal scars result in distressing symptoms and disfiguring blemishes; an understanding of the molecular events that cause such scars, particularly keloids, would make possible the optimisation of both wound healing and treatment. Extracellular signal-regulated protein kinase (ERK) has a crucial role in distinct signalling pathways in different cells, but to date we know of no study on its signalling events in keloid fibroblasts. The purpose of this study was to characterise the expression of tyrosine phosphorylation kinases, particularly that of ERK, in keloids at the protein level by immunoblotting analysis. Studies on phosphorylation were made on cell lysates of three cultures of five different keloid fibroblasts (n = 5), their relatively 'normal' fibroblasts in adjacent skin (rNHDF, n = 5), and normal human dermal fibroblasts (n = 1, standard control). The result showed that ERK signalling molecular protein was more highly phosphorylated in keloid fibroblast culture than in the other two cultures.     

Detection of apoptosis in keloids and a comparative study on apoptosis between keloids, hypertrophic scars, normal healed flat scars, and dermatofibroma

Recent studies have suggested that the regulation of apoptosis during wound healing is important in scar establishment and the development of pathological scarring. In this study, we demonstrate that keloid fibroblasts can be identified as apoptotic cells because of their highly condensed chromatin and discrete nuclear fragments. To further reveal the phenomenon of apoptosis, we quantified the number of terminal deoxynucleotide transferase-mediated dUTP nick-end labeling (TUNEL)-positive cells in surgically resected tissues of keloids (N = 10), hypertrophic scars (N = 10), normal healed flat scars (N = 10), and dermatofibroma (N = 10). The number of TUNEL-positive cells was relatively low, but was significantly higher for the keloid group compared with the normally healed flat scar group (p = 0.004), suggesting reduced cell survival and increased apoptotic cell death in a subpopulation of keloid fibroblasts. Furthermore, the number of TUNEL-positive cells was significantly higher for the keloid group compared with the dermatofibroma group (p = 0.044), suggesting that a subpopulation of keloid fibroblasts may suppress tumorgenicity at a greater rate than dermatofibroma by undergoing cell death. Hypertrophic scars had significantly higher levels of apoptosis than normally healed flat scars (p = 0.033). Therefore, these results suggest that selected fibroblasts in keloids and hypertrophic scars undergo apoptosis, which may play a role in the process of pathological scarring.     

Suppression of in vitro proliferative scar fibroblast contraction by interferon alfa-2b

Increased fibroblast activity and collagen production have been observed frequently in proliferative scars. Previous studies have demonstrated that interferons suppress collagen production by means of normal, keloid, and hypertrophic scar-derived fibroblasts. The fibroblast-populated collagen lattice is an in vitro model used to study fibroblast function. We used fibroblast-populated collagen lattices to evaluate the effect of interferon on fibroblasts harvested from normal human skin, human keloid, and hypertrophic scar tissues. Human recombinant interferon alfa-2b (1000 IU/ml) was added to the culture media. The collagen gel, prepared from rat tail tendon bundles, was overlaid with 5 x 10(4) fibroblast cells. Keloid fibroblast-populated collagen lattices showed the highest contraction. Contraction in all the groups appeared suppressed by interferon alfa-2b during the first 72 hours of study (p < 0.05). The reduction in fibroblast-populated collagen lattice contraction by interferon alfa-2b was similar among the groups. The contractile properties of fibroblasts taken from normal human skin, keloids, and hypertrophic scars in this in vitro study were suppressed by interferon alfa-2b. This suggested that interferon alfa-2b may be beneficial for the treatment of proliferative scars.     

Fibronectin gene expression differs in normal and abnormal human wound healing

The overproduction of fibronectin and type I collagen in keloids and hypertrophic scars implicates altered regulation of extracellular matrix components as an important aspect of these wound healing pathologies. However, little is known about the similarities and differences in extracellular matrix gene expression during normal and abnormal wound healing. This study compared the content of fibronectin messenger RNA and rates of fibronectin protein biosynthesis in fibroblasts derived from normal skin, normal scar, keloid, and hypertrophic scar. Fibronectin expression was enhanced in cells from both normal and abnormal wounds relative to cells from quiescent normal skin. Matched pairs of normal and keloid fibroblasts from the same individuals were also compared, and three of the four pairs showed higher fibronectin expression by the keloid cells at the levels of messenger RNA and protein synthesis. This was consistent with previous studies showing elevated steady state content of fibronectin in keloid cells relative to normal cells from the same individual. Fibronectin messenger RNA and protein content in the tissues from which these cells were derived was examined by in situ hybridization and immunohistochemistry. These studies revealed that in vivo, the steady state content of fibronectin messenger RNA and protein was highest in abnormal wounds, less in most normal scars, and lowest in normal skin. Thus, fibroblasts from keloids and hypertrophic scars overexpressed fibronectin in vivo relative to normal skin and normal scar and retain this characteristic in vitro relative to normal skin. Although normal scars contained little fibronectin protein and messenger RNA, cultured fibroblasts derived from these scars had contents of fibronectin messenger RNA and rates of biosynthesis in vitro similar to those of keloid fibroblasts. This indicates that the fibronectin regulatory pathway in scar fibroblasts is influenced by the tissue environment. These results are discussed with respect to the relationship of fibronectin expression in keloids, hypertrophic scars, and normal wounds in human beings.