间充质干细胞分泌关键蛋白抑制创面修复过程中瘢痕形成的机制研究

hypertrophic or keloid scarring afer severe skin trauma are still the unsolved problems in clinic. Mesenchymal stem cells (MSCs) have been well documented to possess the effect on promoting cutaneous wound healing. However, it is no clear whether MSCs have the inhibition action for skin scar formation during the wound-healing process. In our preliminary experiment, MSCs transplantation significantly inhibit the formation of skin scar based on skin progressive scar model, however, the mechanism involved in its effect is poorly understood. Especially, tranplanted MSCs live for a short while on cutaneous wound, and have not differentiated skin cells enough to to regulate the microenviroment of wounds. So the applicant proposes the hypothesis: transplanted MSCs may have the effect on inhibiting skin scar formation during the wound-healing process by secreting key proteins. Therefore, in this study, the impact of MSCs on the fibroblasts of hypertrophic scars in culture will be examined; gene silencing and gene chip technology will be applied to screen the key proteins working in the process; and the effect of of MSCs secreting key proteins will be validated and the molecular mechanism of BM-MSCs inhibiting skin scar will be clarified further based on skin progressive scar model and gene knockout mouse; The experimental basis can be established to provide a new treatment strategy for anti-scar repair of skin wound.

严重创伤后不良愈合所产生的增生性瘢痕或瘢痕疙瘩是临床亟待解决的难题之一。间充质干细胞（MSCs）被证实对皮肤创面有促愈合效应，然而对愈合后瘢痕的形成是否产生影响尚无报道。申请人前期研究初步证实了MSCs在移植小鼠渐进性皮肤瘢痕模型后抑制瘢痕形成的可能性，但其作用机制尚不明确。特别是移植后的细胞在创面存活时间较短，不足以分化成皮肤细胞改变创面微环境。基于此，申请人认为MSCs移植后很有可能是通过其分泌的活性因子在创面愈合过程中发挥了抑制瘢痕形成的功效。本项目首先探查MSCs分泌成分对瘢痕来源的成纤维细胞产生的影响，并通过基因沉默和基因芯片技术筛选分泌成分中发挥关键作用的主要活性因子，依托小鼠渐进性皮肤瘢痕模型和基因敲除鼠验证分泌的关键因子的作用，阐明其抑制愈合过程中瘢痕形成的分子机制。本项目立足于明确MSCs在创面愈合过程中抑制瘢痕形成作用机制，为皮肤创伤后的抗瘢痕修复策略提供研究基础。

严重创伤后不良愈合所产生的增生性瘢痕或瘢痕疙瘩是临床亟待解决的难题之一。近年来发现间充质干细胞（MSC）移植能够有效降低组织纤维化，但对于皮肤瘢痕的作用尚不明确。本研究发现，移植后的细胞在创面存活时间较短，不足以分化成皮肤细胞改变创面微环境。因此，在本研究中，我们探查了MSC对于瘢痕成纤维细胞及胶原沉积的作用，测试其作用与转化生长因子-β（TGF-β）家族具有相关性。体外研究显示，MSC 条件培养液（CM）能够降低瘢痕成纤维细胞的增殖、α平滑肌肌动蛋白(α-SMA)及胶原表达。而且，MSC 分泌的TGF-β3在炎性环境下呈高表达，阻断TGF-β3的活性后，则可显著拮抗CM对于瘢痕成纤维细胞的作用。在动物实验中发现，依托小鼠渐进性皮肤瘢痕模型验证分泌的关键因子的作用，阐明其抑制愈合过程中瘢痕形成的分子机制。本项目立足于明确MSCs在创面愈合过程中抑制瘢痕形成作用机制，为皮肤创伤后的抗瘢痕修复策略提供研究基础。