Expression of TGF-beta in foreign body reaction and fibrosis agaist titanium implant.

本文对20例异物包裹过程中转化生长因子-β(TGF-β)、血小板衍生生长因子(PDGF)及其受体的原位表达进行了研究。我们用微型钛板作为异物模型，临床用于下颌骨骨折的固定。包埋过程中形成的纤维囊由瘢痕样层和纤维样层组成，前者直接面对异物。免疫组织化学染色显示，只有纤维化层有I型前胶原(PC-I)的表达。纤维化层中的梭形间充质细胞表达转化生长因子-β亚型和受体，以及PDGF-β亚型和受体。相反，疤痕样层几乎没有这样的细胞。免疫荧光双标记法显示，大多数PC-I阳性成纤维细胞在纤维化层同时表达转化生长因子-β和血小板衍生生长因子的异构体和受体。我们的结果表明，在人对异物的包裹过程的维持阶段，转化生长因子-β和血小板衍生生长因子都通过其纤维化层中的受体协同发挥作用，而在瘢痕样层中这种刺激明显减弱。

The present paper addresses in situ expression of transforming growth factor-beta (TGF-beta), platelet-derived growth factor (PDGF), and their receptors in the encapsulation process against foreign body using 20 cases. We dealt with titanium miniplate as a model of foreign body, which was used clinically to fix fractured mandible. Fibrous capsule formed as the encapsulation process was composed of scar-like-and fibrogenic layrs, with the former directly facing the foreign body. By immunohistochemistry using pre-fixed frozen sections, only the fibrogenic layr was characterized by an expression of type I procollagen (PC-I). Spindle-shaped mesenchymal cells in the fibrogenic layr expressed TGF-beta isoforms and receptors, and PDGF isoforms and PDGF beta-receptor. In contrast, the scar-like layr had few such cells. In both layrs, spindle-shaped cells did not expressed Ki-67 in their nuclei.Double immunofluorescence microscopy for the cell identification revealed that most PC-I-positive fibroblasts expressed both isoforms and receptors of TGF-beta and PDGF in the fibrogenic layr. In contrast, a small number of CD68-positive macrophages expressed these.Our results suggest that in the maintenance stage of the human encapsulation process against foreign body, both TGF-beta and PDGF function cooperatively via their receptors in the fibrogenic layr, with such stimuli markedly diminished in the scar-like layr.