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Electron microscopy and immunocytochemistry on endothelial progenitor cells during healing process of burn injury in adult rats

成年大鼠烧伤愈合过程中内皮祖细胞的电镜和免疫细胞化学研究

基本信息

批准号：
13670033
负责人：
DOI Yoshiaki
金额：
$ 1.22万
依托单位：
University of Occupational and Environmental Health
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

项目摘要

Vasculogenesis is defined as a neovascularization process by transformation of vasoformative mesenchymal cells to endothelial progenitor cells (EPCs). Although recent researches insisted that bone marrow-derived EPCs via peripheral blood vessels are mainly involved in vasculogenesis during wound healing process of adult tissues, we have reported that multipotent mesenchymal cells derived from tissue fibroblasts located in several adult tissues transform to EPCs and participate in the acceleration of the vascular growth. This study deals with ultrastructural and immunocytochemical analysis on EPCs during healing process of burn injury. Deeply anesthetized adult Wistar rats received burn injury in their back skin by exposure to heated cylinder for 1 min at 100℃, and then injured tissue were prepared for light microscopic immunocytochemistry and electron microscopy, respectively. At 3 days after receiving burn injury, migration of tissue fibroblasts from intact dermis to injured dermis was often seen. These cells were occasionally associated with endothelial lining of growing capillaries, or in contact with the neighboring ones. They often formed solid cell cords that eventually make contact with the growing capillaries. Since these cells show immunoreactivities for von Willebrand factor and possess many Weibel-Palade (WP) bodies, we defined them as phenotypes of EPCs. Immunoreactivities for VEGF are seen along endothelial lining of growing capillaries and in such EPCs and these for VEGF receptors are detected in the EPCs suggesting that VEGF produced by the endothelial cells activates transformation of tissue fibroblasts to EPCs via receptor mediated fashion. In addition, immunoreactivities for endothelia (ET)-1, big ET-1 and ET converting enzyme (ECE)-1 are seen in such EPCs. Since it is widely accepted that ET-1 and ECE-1 are stored in WP bodies, we consider now that EPCs which are characterized by possessing WP bodies have ability to synthesize ET-1.

血管发生是指血管形成间充质细胞向内皮祖细胞转化的过程。虽然最近的研究认为，骨髓来源的EPCs通过外周血管主要参与成人组织创伤愈合过程中的血管生成，但我们已经报道了来自组织成纤维细胞的多能间充质细胞转化为EPCs并参与加速血管生长。本研究对烧伤愈合过程中内皮祖细胞进行了超微结构和免疫细胞化学分析。成年Wistar大鼠背部皮肤深度麻醉后，置于100℃高温圆筒中1 min，制备损伤组织，分别进行光镜免疫细胞化学和电镜观察。烧伤后第3天，可见组织成纤维细胞从完整真皮向损伤真皮迁移。这些细胞偶尔与生长毛细血管的内皮衬里相连，或与邻近的毛细血管接触。它们通常形成固体细胞索，最终与生长的毛细血管接触。由于这些细胞显示血管性血友病因子的免疫反应性，并拥有许多韦伯-帕拉德（WP）体，我们将其定义为EPCs的表型。沿着生长的毛细血管的内皮衬里和在这样的EPC中沿着观察到VEGF的免疫反应性，并且在EPC中检测到VEGF受体的免疫反应性，这表明由内皮细胞产生的VEGF通过受体介导的方式激活组织成纤维细胞向EPC的转化。内皮素（ET）-1、大ET-1和ET转换酶（ECE）-1在EPCs中呈阳性反应。由于ET-1和ECE-1被广泛接受储存在WP体中，我们现在认为以具有WP体为特征的EPCs具有合成ET-1的能力。