Buoro S, Ferrarese P, Chiavegato A, Roelofs M, Scatena M, Pauletto P, Passerini-Glazel G, Pagano F, Sartore S
Department of Biomedical Sciences, University of Padova, Italy.
Lab Invest. 1993 Nov;69(5):589-602.
Fibrosis of serosa, along with smooth muscle (SM) cell hypertrophy, has been shown to occur in the rabbit bladder after partial outflow obstruction. Identification of cells involved in the serosal thickening can be of primary interest to elucidate the functional changes that this organ undergoes.
Cytoskeletal protein composition of cells present in the thickened serosa at different times from the onset of obstruction (7, 15, 30 and 60 days) was evaluated. This was accomplished by means of a panel of monoclonal antibodies specific for a number of differentiation markers of mesenchymal cells (vimentin, desmin, alpha-actin of SM type, nonmuscle (NM) and SM myosins), and by immunocytochemical and immunochemical techniques.
The immunocytochemical study revealed that cells in serosal thickening follow a two-step maturation process from pre-existing vimentin-positive cells. In the first time period (7 to 15 days of obstruction), these cells predominantly achieved an immunophenotype corresponding to that of a specific myofibroblast subtype (i.e., containing vimentin, NM myosin, and SM alpha-actin). After 30 days from the onset of obstruction, the cytoskeletal protein content of serosal cells, as also revealed by Western blotting experiments, shifted towards that of fetal-type SM cells (i.e., presence of vimentin, NM myosin, SM alpha-actin, and SM myosin isoforms). Distribution of vimentin, desmin, SM alpha-actin, and SM myosin in tissue culture as well as the ultrastructure in vivo very closely resembled that of SM cells. Bromodeoxyuridine incorporation studies indicated that cells accumulated in the serosa of obstructed bladders did not derive, at least initially, from SM cells of the detrusor muscle.
These findings are consistent with the existence of a differentiation process in which resident mesenchymal cells of bladder serosa may transform to myofibroblasts and, subsequently, in fetal-type SM cells during experimental outflow obstruction.
已表明，部分流出道梗阻后，兔膀胱会出现浆膜纤维化以及平滑肌（SM）细胞肥大。确定参与浆膜增厚的细胞对于阐明该器官所经历的功能变化至关重要。
评估了梗阻开始后不同时间（7、15、30和60天）增厚浆膜中细胞的细胞骨架蛋白组成。这是通过一组针对间充质细胞多种分化标志物（波形蛋白、结蛋白、SM型α-肌动蛋白、非肌肉（NM）和SM肌球蛋白）的单克隆抗体，并采用免疫细胞化学和免疫化学技术来完成的。
免疫细胞化学研究表明，浆膜增厚中的细胞从预先存在的波形蛋白阳性细胞开始经历两步成熟过程。在第一个时间段（梗阻7至15天），这些细胞主要获得了与特定肌成纤维细胞亚型相对应的免疫表型（即含有波形蛋白、NM肌球蛋白和SMα-肌动蛋白）。梗阻开始30天后，Western印迹实验也显示，浆膜细胞的细胞骨架蛋白含量向胎儿型SM细胞转变（即存在波形蛋白、NM肌球蛋白、SMα-肌动蛋白和SM肌球蛋白异构体）。波形蛋白、结蛋白、SMα-肌动蛋白和SM肌球蛋白在组织培养中的分布以及体内超微结构与SM细胞非常相似。溴脱氧尿苷掺入研究表明，梗阻膀胱浆膜中积聚的细胞至少最初并非来自逼尿肌的SM细胞。
这些发现与以下分化过程的存在一致，即在实验性流出道梗阻期间，膀胱浆膜中的常驻间充质细胞可能转变为肌成纤维细胞，随后转变为胎儿型SM细胞。
