Hiscott P, Sorokin L, Nagy Z Z, Schlötzer-Schrehardt U, Naumann G O
Department of Ophthalmology, University of Erlangen-Nürnberg, Erlangen, Germany.
Exp Cell Res. 1996 Jul 10;226(1):140-6. doi: 10.1006/excr.1996.0212.
Immunochemical techniques were used to determine whether cells of the avascular corneal stroma (keratocytes) have the ability to synthesize thrombo- spondin 1 (TSP1), a glycoprotein originally described in platelets and more recently implicated in regulating cell behavior (e.g., migration) during wound repair in vascular tissue. Immunoprecipitation experiments with metabolically labeled cells showed that bovine keratocytes in preconfluent cultures produced TSP1, but de novo TSP1 production could not be detected in confluent keratocyte cultures. Immunofluorescence studies of the preconfluent cells revealed that the keratocyte TSP1 was distributed in perinuclear granules and peripheral foci. TSP1 expression also was observed in keratocytes cultured in a collagen matrix model of stromal wound healing and, in this model, immunogold labeling revealed TSP1 foci on keratocyte surfaces adjacent to collagen fibers in the matrices. TSP1 expression was not observed in the syncytial keratocytes of normal bovine cornea. The results indicate that keratocytes have the ability to synthesize TSP1, and do so in vitro under conditions which simulate corneal stroma repair, but suggest that keratocytes in a syncytial arrangement (as in the normal cornea) do not make TSP1. TSP1 may play a role in corneal pathologies which induce keratocytes to change from a syncytial to a wound repair phenotype, such as mechanical damage to the stroma. Local production of TSP1 might provide an alternative source to platelet-derived TSP1 during nonvascularized stromal tissue repair.
免疫化学技术被用于确定无血管的角膜基质细胞（角膜细胞）是否有能力合成血小板反应蛋白1（TSP1），这是一种最初在血小板中发现的糖蛋白，最近被认为在血管组织伤口修复过程中参与调节细胞行为（如迁移）。对代谢标记细胞进行的免疫沉淀实验表明，预汇合培养的牛角膜细胞能产生TSP1，但在汇合的角膜细胞培养物中未检测到TSP1的从头合成。对预汇合细胞的免疫荧光研究显示，角膜细胞TSP1分布于核周颗粒和周边灶中。在基质伤口愈合的胶原基质模型中培养的角膜细胞也观察到了TSP1的表达，在此模型中，免疫金标记显示TSP1灶位于基质中与胶原纤维相邻的角膜细胞表面。在正常牛角膜的合胞体角膜细胞中未观察到TSP1的表达。结果表明，角膜细胞有能力合成TSP1，并且在模拟角膜基质修复的条件下能在体外合成，但提示处于合胞体排列状态（如在正常角膜中）的角膜细胞不产生TSP1。TSP1可能在诱导角膜细胞从合胞体表型转变为伤口修复表型的角膜病变中发挥作用，如基质的机械损伤。在无血管基质组织修复过程中，TSP1的局部产生可能为血小板衍生的TSP1提供替代来源。
