Role of scaffold stiffness dependent durotaxis on development of keloid

瘢痕疙瘩是皮肤纤维化的条件，可以引起轻微的侮辱皮肤，如痤疮或耳洞，或严重的伤害，如烧伤。瘢痕疙瘩的特征在于过度丰富的细胞外基质如胶原的沉积，并且它们的组织学形态具有特征性方式。瘢痕疙瘩好发于胸、肩、肘关节等易受机械牵拉影响的部位。因此，我们认为瘢痕疙瘩成纤维细胞对机械应力的反应可能不同于正常皮肤成纤维细胞。我们使用细胞拉伸装置（NC-500）分析了对机械应力的敏感性，所述细胞拉伸装置具有在其上培养成纤维细胞的硅室。利用基因芯片技术研究了周期性细胞拉伸引起的基因表达差异。我们发现，与正常皮肤成纤维细胞相比，瘢痕疙瘩成纤维细胞编码细胞骨架、膜蛋白和细胞因子的一些基因发生了强烈变化（我们在<th>日本整形外科学会第14届研究理事会会议上报告）。此外，我们通过一组抗体发现瘢痕疙瘩成纤维细胞中rac 1蛋白的表达高于正常皮肤成纤维细胞。此外，我们分析了细胞拉伸后细胞内分子的表达变化。我们将成纤维细胞培养在弹性胶原包被的聚丙烯酰胺凝胶上，发现细胞的形状和增殖率随聚丙烯酰胺凝胶的硬度而变化。

Keloids are skin fibrotic conditions that can be caused by minor insults to skin, such as acne or ear piercing, or by severe injuries such as burns. Keloids are characterized by an overabundant deposition of extra-cellular matrix such as collagen, and their histologic morphology has a characteristic manner. Keloid occurs more often on chest, shoulder or elbow-joint etc. which is easily affected by mechanical stretch. So we consider that the response to mechanical stress of fibroblast derived from Keloid may be different from that of normal skin fibroblast. We analyzed the sensitivity to mechanical stress using cell stretch apparatus (NC-500) which has silicon chambers on which the fibroblasts are cultured. We investigated differential gene expression in response to cyclic cell stretching by gene chip array. We found that some genes of keloid fibroblasts encoding cellular skeleton, membrane proteins and cytokines were strongly changed compared to normal skin fibroblasts (We reported at The 14^<th> Research Council Meeting of Japan Society of Plastic and Reconstructive Surgery). Furthermore we found that the expression of rac1 protein is higher in keloid fibroblasts than in normal skin fibroblasts by panel of antibodies. In addition, we analyzed expression change of intracellular molecules after cell stretching. We cultured fibroblasts on elastic collagen coated polyacrylamide gel whose hardness is changeable and we found that cell shape and proliferation rate are variable depending on hardness of polyacrylamide gel.