槲皮素对瘢痕疙瘩成纤维细胞胶原合成的影响

目的研究槲皮素对瘢痕疙瘩成纤维细胞胶原合成的影响,探讨其作用机理。方法体外培养瘢痕疙瘩及正常皮肤成纤维细胞,应用羟脯氨酸比色法对不同药物浓度处理后成纤维细胞胶原合成量进行分析;RT-PCR及Real-timePCR检测Ⅰ、Ⅲ型胶原及TGFβ-1基因表达水平。结果槲皮素可抑制体外培养瘢痕疙瘩成纤维细胞胶原合成,该作用呈剂量依赖效应;槲皮素可降低Ⅰ、Ⅲ型胶原和TGFβ-1基因mRNA水平。结论槲皮素对于瘢痕疙瘩成纤维细胞胶原合成有显著抑制效应,其作用机制之一为通过抑制TGFβ-1基因在转录水平降低了前胶原mRNA水平,因而使成纤维细胞胶原合成减少。     

己酮可可碱对瘢痕疙瘩成纤维细胞增殖、胶原合成及转化生长因子-β1表达的影响北大核心CSCD

目的探讨己酮可可碱对瘢痕疙瘩成纤维细胞增殖、胶原合成及转化生长因子（TGF）-β1表达的影响。方法取人瘢痕疙瘩及正常皮肤组织培养的第5～8代成纤维细胞,在含有0．1—3g／L己酮可可碱的环境中培养。应用噻唑蓝（M1Tr）法检测成纤维细胞增殖,双抗体夹心-ELISA法测定TGF—β1表达,RT—PCR检测I、Ⅲ型前胶原mRNA表达。结果0．1～2g／L己酮可可碱能明显抑制瘢痕疙瘩和正常皮肤成纤维细胞的增殖,呈明显的量效一时效关系,抑制作用在浓度2g／L时达到最高。浓度为0．5～2g／L时己酮可可碱能降低瘢痕疙瘩和正常皮肤成纤维细胞TGF—B1表达,1或2g／L时己酮可可碱能降低瘢痕疙瘩和正常皮肤成纤维细胞I、Ⅲ型前胶原mRNA表达。结论己酮可可碱对瘢痕疙瘩和正常皮肤成纤维细胞的增殖、TGF—β1以及I、Ⅲ型前胶原表达均有明显的抑制作用。     

核因子Ⅰ-C对血小板源性生长因子调节皮肤成纤维细胞转化生长因子β信号通路的抑制作用

目的:探讨核因子(NF)Ⅰ对血小板源性生长因子(PDGF)增强皮肤成纤维细胞转化生长因子β(TGF-β)信号通路的影响作用。方法:构建NFⅠ-C基因慢病毒载体并且确定慢病毒转染成纤维细胞最佳条件,采用Western印迹法测定PDGF对经NFⅠ-C基因病毒转染后成纤维细胞的TGF-β1及其受体Ⅱ(TβRⅡ)蛋白表达的影响作用。结果:(1)NFⅠ-C慢病毒载体转染皮肤成纤维细胞的最佳转染值为50;(2)皮肤成纤维细胞经NFⅠ-C慢病毒转染后NFⅠ-C蛋白的表达较非病毒转染细胞显著升高(P0.05);(3)正常皮肤成纤维细胞与PDGF共同培养48 h后TGF-β1和TβRⅡ蛋白表达较空白对照显著升高(P0.05);(4)皮肤成纤维细胞经NFⅠ-C慢病毒转染后与PDGF共同培养后48 h后TGF-β1和TβRⅡ蛋白表达均较正常对照皮肤成纤维细胞和空病毒转染皮肤成纤维细胞显著降低(P0.05)。结论:血小板源性生长因子可增强皮肤成纤维细胞TGF-β1和TGF-β受体Ⅱ的表达,而NFⅠ-C表达增加可抑制PDGF增强TβRⅡ表达的作用。     

半乳糖β-1，4-糖苷键在瘢痕疙瘩组织中的定位与表达北大核心CSCD

目的探讨半乳糖β-1,4-糖苷键在瘢痕疙瘩组织中的合成、定位及糖蛋白半乳糖基化在瘢痕疙瘩形成机制中的作用。方法Leetin印迹法观察瘢痕疙瘩、增生性瘢痕和正常皮肤组织中糖蛋白的糖基化水平;饱和苦味酸一天狼猩红偏振光法观察组织学结构及胶原的形态与分布。分析组织中Ⅰ、Ⅲ型胶原的比例;蓖麻凝集素-Ⅰ免疫荧光组化法分析组织中半乳糖β-1,4-糖苷键的表达与定位,并与Ⅰ型前胶原d1共定位。结果经糖链染色,与正常皮肤组织相比,瘢痕疙瘩组织在约30000和40000处糖蛋白的半乳糖β-1,4-糖苷键表达增高。偏振光显微镜显示,瘢痕疙瘩组织中含有大量Ⅰ型胶原纤维,约占（71．53±4．03）％,Ⅰ、Ⅲ型胶原比例为2．56±0．53,高于正常皮肤组织（P〈0．05）。免疫荧光发现,半乳糖β-1,4-糖苷键均匀分布在瘢痕疙瘩组织成纤维细胞胞膜和胞质内,与正常皮肤组织相比其表达量明显增加,且与Ⅰ型前胶原α1存在共定位。结论瘢痕疙瘩组织中存在着半乳糖β-1,4一糖苷键的表达变化,且主要定位于成纤维细胞,提示半乳糖β-1,4-糖苷键可能参与瘢痕疙瘩修复过程中纤维过度增生相关因子的修饰调控。     

瘢痕疙瘩成纤维细胞胶原合成的实验研究

目的 探讨瘢痕疙瘩中胶原过度聚集的原因.方法 从正常皮肤与活跃增生瘢痕疙瘩标本分别培养真皮成纤维细胞,采用³H-脯氨酸掺入法分别检测单层培养及胶原凝胶三维培养体系中成纤维细胞的胶原合成量.用斑点杂交法检测单层培养细胞的人前.α1(Ⅰ)型胶原mRNA水平.结果 瘢痕疙瘩成纤维细胞Ⅰ型胶原mRNA水平升高,其胶原合成量也显著高于正常真皮成纤维细胞(P<0.01).结论 在增生活跃瘢痕疙瘩中,成纤维细胞胶原合成功能处于活化状态,胶原合成增加是导致胶原过度积聚的重要原因.     

系统性硬皮病患者成纤维细胞转化生长因子β 1与Ⅰ型胶原mRNA表达的研究

目的探讨系统性硬皮病成纤维细胞自身分泌的转化生长因子(TGF)β1是否影响Ⅰ型胶原α1链(COL1A1)mRNA表达。方法采用核酸原位杂交和免疫印迹法分别测定培养的硬皮病和正常人成纤维细胞中COL1A1mRNA的表达和TGF-β1蛋白质的含量。结果硬皮病组成纤维细胞COL1A1mRNA(A值x±s为905.09±20.36)表达较对照组354.17±30.89明显增高。硬皮病组和对照组成纤维细胞的COL1A1mRNA表达均存在异质性,硬皮病组COL1A1mRNA高表达的成纤维细胞数x±s为27.33%±4.63%明显高于对照3.67%±1.20%,而对照组低COL1A1mRNA表达的成纤维细胞数62.33%±3.53%明显高于硬皮病组14.33%±4.91%。硬皮病组内各细胞株间,高、中、低胶原表达的细胞数差异无显著性。硬皮病组和对照组成纤维细胞中TGF-β1蛋白质表达差异无显著性。结论硬皮病成纤维细胞Ⅰ型胶原mRNA表达增多,这种表达增多与成纤维细胞自身合成TGF-β1的水平可能无关。     

曲尼司特对人正常皮肤和瘢痕疙瘩成纤维细胞部分细胞因子表达的影响

目的 ：研究曲尼司特对正常皮肤和瘢痕疙瘩成纤维细胞转化生长因子-β1（TGF-β1）、碱性成纤维细胞生长因子（bFGF）和白介素-6（IL-6）表达的影响。方法：在体外无血清培养的人正常皮肤成纤维细胞和瘢痕疙瘩成纤维细胞中，分别加入0、10、25、50和250μg／mL曲尼司特孵育24、72、96h，用双抗体夹心酶联免疫吸附试验（ABC—ELISA）法测定其上清液中TGF-β1、bFGF和IL-6的表达水平。结果：与对照组相比。25、50和250μg／mL曲尼司特能抑制瘢痕疙瘩成纤维细胞TGF-β1的表达；50μg／mL和250μg／mL曲尼司特能增加瘢痕疙瘩成纤维细胞bFGF的表达；10～250μg／mL曲尼司特可降低IL-6的表达，上述改变在一定时段差异有统计学意义（P〈0．05）。不同浓度曲尼司特对正常皮肤成纤维细胞的影响相似。结论：曲尼司特能降低瘢痕疙瘩成纤维细胞TGF-β1的产生。增加bFGF的合成，减少IL-6的表达，这或许可解释其在抑制异常瘢痕形成中的作用。     

低氧对系统性硬化病患者皮肤成纤维细胞胶原蛋白合成的影响

目的 研究低氧对系统性硬化病(SSc)患者和正常人皮肤成纤维细胞胶原蛋白合成及胶原基因表达的影响。方法 分别以5例SSc患者和5例正常人皮肤成纤维细胞系作为实验对象。将成纤维细胞分别放入20%正常氧和2%低氧分压环境中培养,用分光光度仪测定细胞培养基上清液中羟脯氨酸含量,并折算成胶原蛋白含量。用Trizol提取细胞总RNA,用RT-PCR方法测定其中Ⅰ型和Ⅲ型前胶原mRNA的表达。结果 培养至第6天,低氧分压条件下,SSc患者皮肤成纤维细胞培养基中胶原蛋白含量比正常氧分压条件下显著增加(t=3.97,P=0.0041);正常人皮肤成纤维细胞培养基中胶原蛋白含量此时也显著增加(t=2.63,P=0.0302)。培养至第3天,低氧分压条件下,SSc成纤维细胞Ⅰ型和Ⅲ型前胶原mRNA表达量比正常氧分压条件下均有显著增加(Ⅰ型:t=5.81,P=0.0004;Ⅲ型:t=6.44,P=0.0002);正常人皮肤成纤维细胞此时的Ⅰ型和Ⅲ型前胶原mRNA表达量与SSc患者相似,低氧分压条件下比正常氧分压条件下均有显著增加(Ⅰ型:t=4.40,P=0.0023;Ⅲ型:t=2.24,P=0.0453)。结论 低氧状态下,SSc患者和正常人皮肤成纤维细胞胶原蛋白合成均有增加,Ⅰ型和Ⅲ型前胶原mRNA表达也均增加.低氧可能是皮肤硬化的一个相关因素。     

人真皮网状层成纤维细胞在瘢痕疙瘩皮损组织中的表达与分布

【摘要】 目的 探讨人真皮乳头层成纤维细胞（Fp）、网状层成纤维细胞（Fr）和肌成纤维细胞（MFB）在瘢痕疙瘩皮损组织中的表达与分布。方法 2019年5 - 12月在武汉大学人民医院皮肤科门诊确诊的15例瘢痕疙瘩患者,男8例,女7例,年龄20 ~ 50岁,取皮损组织,以15例年龄匹配的女性乳房整形术正常皮肤组织为对照。采用双重免疫荧光染色法检测成纤维细胞活化蛋白（FAP）、CD90和α平滑肌肌动蛋白（α-SMA）在瘢痕疙瘩和正常皮肤组织中的分布。从3例正常皮肤和3例瘢痕疙瘩组织中分离成纤维细胞原代培养,采用10 ng/ml 转化生长因子β1（TGF-β1）体外处理两组细胞0 ~ 48 h,观察细胞表型的变化,荧光定量RT-PCR和Western印迹检测FAP、CD90和α-SMA mRNA和蛋白表达。两组间差异比较采用t检验。结果 免疫荧光结果显示,正常皮肤组织中,FAP+/CD90-细胞主要分布在真皮浅层,FAP-/CD90+细胞集中在真皮深层,CD90+细胞几乎不表达α-SMA;瘢痕疙瘩组织深层可见大量FAP+和CD90+细胞,大量CD90+细胞同时表达α-SMA。双重免疫荧光染色显示,正常皮肤成纤维细胞几乎不表达α-SMA,瘢痕疙瘩成纤维细胞表达α-SMA;TGF-β1处理24 h时,正常成纤维细胞和瘢痕疙瘩成纤维细胞α-SMA+细胞荧光强度（21.058 ± 0.709、27.112 ± 0.097）均高于未处理组（11.312 ± 0.636、21.306 ± 0.464）,t值为22.430、13.370,P < 0.05。RT-PCR和Western印迹显示,TGF-β1处理48 h时,瘢痕疙瘩成纤维细胞FAP、CD90、α-SMA mRNA相对表达水平（92.610 ± 3.667、1.366 ± 0.105、3.240 ± 0.141）与蛋白表达水平（0.652 ± 0.073、1.046 ± 0.119、0.946 ± 0.117）均高于处理前（均P < 0.05）。结论 瘢痕疙瘩组织真皮深层的CD90+（Fr）细胞异常增生,提示针对真皮深层异常增殖活跃的FAP-/CD90+（Fr）细胞群进行定向干预可能提高瘢痕疙瘩治疗疗效。     

Dermatopontin expression is decreased in hypertrophic scar and systemic sclerosis skin fibroblasts and is regulated by transforming growth factor-beta1, interleukin-4, and matrix collagen

Dermatopontin is a recently discovered extracellular matrix protein with proteoglycan and cell-binding properties and is assumed to play important roles in cell-matrix interactions and matrix assembly. In this study we examined the expression of dermatopontin mRNA and protein in skin fibroblast cultures from patients with hypertrophic scar and patients with systemic sclerosis. Dermatopontin mRNA and protein levels were reduced in fibroblast cultures from hypertrophic scar lesional skin compared with fibroblasts from normal skin of the same hypertrophic scar patient. Fibroblast cultures from systemic sclerosis patient involved skin also showed significantly reduced expression of dermatopontin compared with normal skin fibroblasts from healthy individuals. We also investigated the effects of cytokines and matrix collagen on dermatopontin expression in normal cultured fibroblasts. Transforming growth factor-beta1 increased dermatopontin mRNA and protein levels, while interleukin-4 reduced dermatopontin expression. Substrate coated with type I collagen reduced dermatopontin mRNA levels, the reduction being more prominent in three-dimensional collagen matrices. Our results suggest that the decreased expression of dermatopontin is associated with the pathogenesis of fibrosis in hypertrophic scar and systemic sclerosis, and that the effect of the cytokines and matrix collagen on dermatopontin may have important implications for skin fibrosis.     

Hexose sugars differentially alter collagen gene expression and synthesis in fibroblasts derived from granulation tissue,hypertrophic scar and keloid

Clinical observations have suggested that sugar and honey enhance granulation tissue formation and in vitro studies have shown that monosaccharide sugars stimulate mesenchymal and endothelial cells. In this study, the effects of glucose, fructose, galactose and mannose on type I and type III collagen gene expression and synthesis were studied in granulation tissue, hypertrophic scar and keloid fibroblast cultures. Glucose elevated both type I and type III collagen mRNAs in hypertrophic scar fibroblasts. Fructose increased type III collagen mRNA almost sevenfold in granulation tissue fibroblasts. Galactose caused an increase in type I and type III collagen mRNAs in granulation tissue fibroblasts and hypertrophic scar fibroblasts but, in contrast, mannose decreased type I and type III collagen levels in hypertrophic scar and keloid fibroblasts. Analysis of aminoterminal propeptides of type I and type III collagen (PINP and PIIINP) revealed that glucose decreased the amount of PINP in granulation tissue and keloid fibroblasts, whilst fructose decreased the amount in all the fibroblast cell lines studied. Galactose caused a decrease in the synthesis of type I collagen in all cell lines but a decrease was seen in type III collagen only in hypertrophic scar fibroblasts. Mannose decreased the amount of PINP in all cell lines but a decrease in the amount of PIIINP was seen only in granulation tissue fibroblasts. The effect of sugars on the ratio type I/type III collagen was negligible or decreasing with the exception of galactose, which increased the ratio in hypertrophic scar fibroblasts. The results suggest that glucose, fructose and galactose have no significant value in the stimulation of collagen synthesis in vitro. Mannose may have value in the prevention or treatment of abnormal scars.     

Reduced collagenase gene expression in fibroblasts from hypertrophic scar tissue

Summary The major histopathological feature of hypertrophic scar lesions is fibrosis. characterized by excessive accumulation of collagen. The purpose of this study was to determine if there is not only increased expression of collagen but also decreased expression of collagenase in hypertrophic scar fibroblasts. We compared the expression of mRNA for of α₁ (I) and α₁ (III) collagen, and collagenase in cultured fibroblasis from different portions of hypertrophic scars and normal dermis. the hypertrophic scar fibroblasts. increased levels of α₁ (I) and α₁ (III) collagen mRNAs were observed in fibroblasts from the edge and outside of scar tissue, while normal levels were noted in fibroblasts from the centre of this tissue. In contrast. decreased levels of collagenase mRNA were found in the hypertrophic scar fibroblasts. The reductions were centre (25% of the control) greater than the edge (43% of the control) greater than the outside (84% of the control). The changes in the collagenase mRNA levels of the hypertrophic scar fibroblasts correlated well with decreased collagenolytic activity as determined by the degradation rate of fluorescent isothiocyanate-labelled type I collagen in fibroblast culture supernatant. These results suggest that decreased expression of collagenase in hypertrophic scar fibroblasts may be one possible cause for the excessive accumulation of collagen in the skin lesions of hypertrophic scars.     

Studies of transforming growth factors beta 1-3 and their receptors I and II in fibroblast of keloids and hypertrophic scars

Keloids are benign skin tumours occurring during wound healing in genetically predisposed patients. They are characterized by an abnormal deposition of extracellular matrix components, particularly collagen. There is uncertain evidence that transforming growth factor-beta (TGFss) is involved in keloid formation. Therefore we investigated the expression of TGFss1, 2 and 3 and their receptors in keloids, hypertrophic scars and normal skin. Dermal fibroblasts were obtained from punch biopsies of patients with keloids and hypertrophic scars and from normal skin of healthy individuals. Total RNA was isolated and the expression of TGFss1, 2 and 3 and of TGFss receptors I and II (TGFssRI and II) was analysed by real-time PCR using the Lightcycler technique. Our data demonstrate significantly lower TGFss2 mRNA expression in hypertrophic scar fibroblasts as compared with fibroblasts derived from keloids and normal skin (p<0.05). In contrast, TGFss3 mRNA expression was significantly lower in keloid fibroblasts in comparison with fibroblasts derived from hypertrophic scar and normal skin (p<0.01). TGFssRI mRNA expression was significantly decreased in hypertrophic scar fibroblasts (p<0.01) and TGFssRII mRNA expression was decreased in keloids compared with hypertrophic scar fibroblasts (p<0.001). The ratio of TGFssRI/TGFssRII expression was increased in keloids compared with hypertrophic scar and normal skin fibroblasts. As recently supposed, an increased TGFssRI/TGFssRII ratio could promote fibrosis. Therefore our data support a possible role of TGFssRI and TGFssRII in combination with a certain TGFss expression pattern as fibrosis-inducing factors in keloids.     

Wnt/β-catenin pathway forms a negative feedback loop during TGF-β1 induced human normal skin fibroblast-to-myofibroblast transition

Background

Fibroblast-to-myofibroblast transition is a key event during wound healing and hypertrophic scar formation. Previous studies suggested Wnt/β-catenin signaling might be involved in the wound healing. However, its specific role in skin fibroblast-to-myofibroblast transition remains unclear.

Objective

To investigate the specific role of β-catenin during the transforming growth factor-β1 induced normal skin myofibroblasts transition.

Methods

By real-time quantitative polymerase chain reaction, Western-blot and immunocytochemistry, the activation of Wnt/β-catenin pathway in cultured human normal skin fibroblasts during TGF-β1 induced fibroblast-to-myofibroblast transition was investigated. The effects of β-catenin on myofibroblasts transition were also investigated when SB-216763, over-expression and siRNA of β-catenin were utilized. In addition, fibroblasts populated collagen lattices contraction assays were conducted to examine the effects of β-catenin on the contractility of the fibroblasts induced by TGF-β1. Furthermore, the effects of β-catenin on the expression of α-smooth muscle actin and collagen types I and III in hypertrophic scar derived fibroblasts were studied.

Results

The expression of Wnts mRNA and β-catenin protein was up-regulated by TGF-β1 stimulation during the myofibroblasts transition. Both of SB-216763 and β-catenin over-expression was paralleled with decreased expression of α-smooth muscle actin, collagen types I and III, while siRNA targeting β-catenin leads to up-regulation of α-smooth muscle actin, collagen types I and III. The increased contractility and α-smooth muscle actin expression of the fibroblasts in the collagen lattices induced by TGF-β1 was inhibited by SB-216763. In addition, the expression levels of α-smooth muscle actin, collagen types I and III in hypertrophic scar derived fibroblasts were also down-regulated by SB-216763.

Conclusion

Specifically in normal skin fibroblasts, β-catenin might be involved in the myofibroblasts transition and negatively regulate the TGF-β1-induced myofibroblast transition.     

A fibroblast cell line cultured from a hypertrophic scar displays selective downregulation of collagen gene expression: barely detectable messenger RNA levels of the proα1(III) chain of type III collagen

The present study was designed to investigate the expression of type I, III and VI collagens by a fibroblast cell line initiated from a hypertrophic scar. The same tissue has previously been demonstrated to display markedly elevated expression of type I and III collagen mRNAs in vivo. Unexpectedly, slot-blot and Northern hybridizations revealed a barely detectable steady-state level of pro1(III) collagen chain mRNA in cultured hypertrophic scar fibroblasts. The levels of pro1(I) and 2(VI) collagen chain mRNAs were essentially the same in fibroblasts cultured from hypertrophic scar and in fibroblasts cultured from normal skin. However, Northern blot analyses indicated that the ratio of 5.8 kb to 4.8 kb species of pro1(I) collagen mRNA was slightly reduced in fibroblasts originating from the hypertrophic scar compared to that in normal fibroblasts. When normal fibroblasts were incubated in conditioned medium from hypertrophic scar cultures, the expression of pro1(III) collagen chain mRNA decreased to a markedly lower level. Our studies suggest that collagen synthesis by fibroblasts in hypertrophic scars is stimulated by humoral factors which are active only in vivo. Furthermore, the results suggest that fibroblasts cultured from hypertrophic scar display a selective downregulation of different collagen genes and that this downregulation is exerted through an autocrine mechanism.     

EGCG inhibits hypertrophic scar formation in a rabbit ear model

Objective

Hypertrophic scarring is a common skin fibro-proliferative disease, but currently there has no satisfactory drugs for anti-scar treatments. Previous study showed that epigallocatechin gallate (EGCG), the main catechin in green tea, improved wound healing and tissue fibrosis in both rats and mice. In the present study, the therapeutic effects of EGCG on hypertrophic scar were analyzed using a rabbit ear hypertrophic scar model.

Materials

A rabbit ear model of hypertrophic scarring was used. DMSO, 0.5 mg EGCG/wound, 1.0 mg EGCG/wound or triamcinolone were injected subcutaneously once a week for 4 weeks. The scar elevation index (SEI) was measured using HE staining images, the collagen fibers were examined by Masson’ trichrome staining images, and the number of capillaries in hypertrophic scar were calculated by CD31 staining images. The mRNA levels in the scar tissues were detected by quantitative real-time polymerase chain reaction (qRT-PCR).

Results

Gross observation and histological evaluation showed the inhibitory effects of EGCG on hypertrophic scar formation at both doses, and decreased scar height and SEI were detected. EGCG also attenuated the mean collagen area fraction and decreased the number of capillaries in scar tissues. qRT-PCR revealed that EGCG significantly inhibited the mRNA expression of TGF-β1, Col I, Col III, α-SMA, and eNOS.

Conclusion

EGCG may serve as a useful candidate therapeutic drug for hypertrophic scar via inhibiting fibrotic gene expression and suppressing angiogenesis.     

Loureirin B inhibits fibroblast proliferation and extracellular matrix deposition in hypertrophic scar via TGF‐β/Smad pathway

The ethanolic extract of Resina Draconis (RDEE) has been reported beneficial to normal wound healing yielding more regularly arranged collagen fibres. Loureirin B, a major component in RDEE, has been supposed to be effective on the prevention and treatment of pathological scars. To investigate the therapeutic effects of loureirin B on hypertrophic scar (HS), fibroblasts from human HS and normal skin (NS) were isolated. Results showed that loureirin B dose‐dependently downregulated both mRNA and protein levels of type I collagen (ColI), type III collagen (ColIII) and α ‐ smooth muscle actin (α ‐ SMA) in HS fibroblasts. Loureirin B also suppressed fibroblast proliferative activity and redistributed cell cycle, but did not affect cell apoptosis. In vivo rabbit ear scar model, loureirin B significantly improved the arrangement and deposition of collagen fibres, decreased protein levels of ColI, ColIII and α ‐ SMA and suppressed myofibroblast differentiation and scar proliferative activity. In NS fibroblasts, loureirin B effectively inhibited TGF‐β1‐induced upregulation of ColI, ColIII and α‐SMA levels, myofibroblast differentiation and the activation of Smad2 and Smad3. Loureirin B also affected mRNA levels of major MMPs and TIMPs in TGF‐β1‐stimulated fibroblasts. Taken together, this study demonstrates that loureirin B could downregulate the expression of fibrosis‐related molecules by regulating MMPs and TIMPs levels, inhibit scar fibroblast proliferation and suppress TGF‐β1‐induced fibrosis, during which TGF‐β1/Smad2/3 pathway is likely involved. These findings suggest that loureirin B is a potential therapeutic compound for HS treatment.     

Distinct patterns of collagen gene expression are seen in normal and keloid fibroblasts grown in three-dimensional culture

The purpose of this study was to examine collagen gene expression in various types of scar fibroblasts as well as normal fibroblasts in a novel three-dimensional culture system and to compare them with those in a monolayer culture system. Cells in three-dimensional culture formed multiple layers within the self-produced dense extracellular matrix and formed a dermis-like structure. In monolayer culture, both normal and scar fibroblasts continued to express high levels of mRNA for proα1(I) and proα1(III) collagens. However, in three-dimensional culture, the mRNA levels gradually declined in normal fibroblasts. In contrast, mRNA levels remained high in keloid and hypertrophic scar fibroblasts. Atrophic scar fibroblasts demonstrated similar changes to normal fibroblasts in three-dimensional culture. When we compared mRNA expression in fibroblasts from the centre and the edge of hypertrophic scar, cells from the centre showed a persistently decreased level of collagenase mRNA expression. These results suggest that the mRNA expression pattern of proα1(I) and proα1(III) collagens varies depending on the culture system. Fibroblasts from keloids and hypertrophic scar may have a defective system of down-regulation in extracellular matrix metabolism.