力学刺激通过TGF-β1/Smads信号通路调控巩膜结构重塑的分子机制研究

High myopia is the primary cause of blind eye disease. The high myopia occurrence is accompanied by scleral structure remodeling. However, the mechanism of scleral structure remodeling is still essentially unknown. Previously we have demonstrated that the mechanical stimulation, TGF-βl and collagen were closely related with scleral structure remodeling. In this project, the model of high myopia and regulating the contraction of the ciliary body to change the stress state of the sclera will be applied to investigate the internal connection among the scleral structure remodeling, biomechanical property, collagen and TGF β1/Smads signaling pathway; then the scleral fibroblasts will be cultured in mechanical environment by the Flexcell system and be treated by TGF-βl, TGFBR1 inhibitor and recombinant lentiviral vector LV-Smads-siRNA to investigate the regulatory effect on collagen expression through TGF β1/Smads signaling pathway. The project study the molecule mechanism of mechanical stimulation regulate scleral structure remodeling through TGF β1/Smads signaling pathway, which could further understand the mechanism of eye emmetropization and high myopia. These results can provide theoretic direction for the prevention and cure of sclera-related disease with the target of collagen, especially the high myopia.

高度近视眼是致盲性眼病的首因，其发生过程伴随着巩膜结构重塑。申请人前期研究发现：力学刺激、TGF-βl和胶原与巩膜结构重塑存在密切的关系，但调控机制尚不明确。本项目拟通过建立高度近视眼动物模型、药物调节实验动物睫状体收缩改变巩膜受力状态等手段，阐明巩膜结构重塑、巩膜生物力学特性、胶原蛋白和TGF-βl/Smads信号通路之间的内在联系；进一步通过Flexcell系统对巩膜成纤维细胞进行力学环境培养，用外源TGF-βl、TGFBR1抑制剂和重组慢病毒LV-Smads-siRNA处理细胞，明确力学刺激下TGF-βl/Smads信号通路对巩膜成纤维细胞胶原表达的调控作用，进而从动物、组织、细胞和分子水平明确力学刺激通过TGF-βl/Smads信号通路调控巩膜结构重塑的分子机制，进一步解释眼球正视化机制和高度近视眼发生机制，为生长发育早期以胶原为靶点防治高度近视眼等巩膜相关疾病提供理论依据。

我国青少年近视率居世界第一，近视眼的发生与巩膜胶原表达和结构重塑密切相关，但其生物力学机制尚不明确。本项目通过建立高度近视眼动物模型、药物调节实验动物睫状体收缩，研究了巩膜结构的重塑过程并对巩膜组织进行力学因素分析；通过Flexcell系统对巩膜成纤维细胞进行力学环境培养，研究了力学刺激对巩膜成纤维细胞胶原表达和代谢的调控机制。本项目研究发现在近视发生时胶原降解高于合成，胶原原纤维直径变小，巩膜变薄，力学特性下降，并导致巩膜成纤维细胞所受的力学环境发生改变；长期持续的睫状体收缩不影响角膜组织结构和力学特性，但影响赤道部巩膜和后部巩膜组织的力学特性、胶原原纤维直径和胶原含量，赤道部巩膜和后部巩膜组织的这些变化可能导致巩膜和眼球变形，进而影响视觉功能和诱发近视；力学刺激通过TGF-β1信号通路调控巩膜成纤维细胞胶原代谢，适当的力学刺激有利于巩膜基质的重塑，持续较大的力学刺激促进巩膜基质的降解；TGF-β1通过调控巩膜成纤维细胞的细胞增殖活性以及胶原表达和代谢，进而影响巩膜生长和结构重塑。本研究表明巩膜胶原的表达和重塑是近视眼巩膜重塑的关键因素，力学因素的改变影响巩膜的生长和近视发生，在正视化和近视过程中，以及长时间的睫状体收缩，巩膜的胶原表达和代谢发生均改变，使得胶原原纤维重塑，进而引起巩膜结构和力学特性发生改变，力学环境的改变影响巩膜成纤维细胞的胶原表达和代谢。