Mechanism investigation of signal transduction on scar tissue formation of palatal mucosa

本研究的目的是：1.建立用于研究大鼠腭外伤听力模型的器官培养系统；SMAD和ASK-1介导成纤维细胞向肌成纤维细胞分化的信号转导机制研究。为了建立离体器官培养模型，在切除腭粘骨膜后，采用发育中的未成熟瘢痕组织和正常腭黏膜的外植体在体内观察肌成纤维细胞的形成。最佳培养条件为无血清Waymouth’s MB 752/1培养基，37℃，含55%O2/5%CO2的潮湿气氛中培养。这些结果表明，所建立的模型为进一步的研究提供了一个有用的体外实验工具。成纤维细胞生长因子（Fibroblast growth factors, FGFs）调节细胞生长和分化，在组织修复和重塑过程中发挥重要作用。我们之前已经证明，基础FGF在损伤部位广泛表达。由于FGF受体（FGFRS）的存在决定了细胞的反应性，我们通过免疫组织化学检测了FGFR1、FGFR2和FGFR3在全层切除伤口修复过程中的表达定位，直至伤口愈合后28天。在肌成纤维细胞细胞核中观察到FGFR1的强表达，其特征是α-平滑肌（α-SM）肌动蛋白表达。在肌成纤维细胞的细胞核中也观察到FGFR2的弱表达。相比之下，在伤口愈合过程中，成纤维细胞中没有FGFR3的染色。此外，肌成纤维细胞的潜在诱导剂转化生长因子-β1 （TGF-β1）在体外培养的腭成纤维细胞核中增强了FGFR1和FGFR2的表达。这些发现表明，在伤口愈合过程中，肌成纤维细胞中的FGFR1和FGFR2可能负责FGF的信号转导。

The purpose of studies was, 1.establishment of the organ culture system for the investigation of rat palatal wound hearing model, and, 2.mechanism investigation of signal transduction of SMAD and ASK-1 mediated differentiation from fibroblasts into myofibroblasts.1.In order to establishing an in vitro organ culture model, after excision of palatal mucoperiosteum, explants from the developing immature scar tissue and from the normal palatal mucosa were used to observe myofibroblasts in vivo. The optimal culture condition was confirmed that xplants were cultured in the gas-liquid interface in serum-free Waymouth's MB 752/1 medium and in a humid atmosphere containing 55%O2/5%CO2 at 37 ℃. These results demonstrate that the established model provides a useful in vitro experimental tool for further investigation.2.Fibroblast growth factors (FGFs) regulate cell growth and differentiation and play crucial roles in the process of tissue repair and remodeling. We have previously shown that basic FGF is widely expressed at the injured site. Since the presence of FGF receptors (FGFRS) determines cellular responsiveness, we examined the localization of FGFR1, FGFR2 and FGFR3 expression by immunohistochemistry throughout the repair of full thickness excisional wounds up to 28 days after wounding. Strong expression of FGFR1 was observed in the nuclei of myofibroblasts, which are characterized by α-smooth muscle (α-SM) actin expression. The weak expression of FGFR2 was also observed in the nuclei of myofibroblasts. In contrast, there was no staining for FGFR3 in fibroblasts through the wound healing process. In addition, transforming growth factor-β1 (TGF-β1), a potential inducer of myofibroblasts, enhanced the expression of FGFR1 and FGFR2 in the nuclei of palatal fibroblasts in vitro. These findings suggest that FGFR1 and FGFR2 in myofibroblasts may be responsible for the signal transduction of FGF during the wound healing process.