TGF-β1调控破骨/成骨耦联在废用性骨质疏松症中的作用及机制研究

Disuse osteoporosis is an important type of secondary osteoporosis, and its high incidence is closely related to the increase in long-term bedridden patients caused by aging. Disuse osteoporosis is characterized by uncoupling between bone resorption by osteoclast and bone formation by osteoblast. However, the key regulatory factors and regulatory mechanisms of the uncoupling remain unclear. TGF-β1 can affect the migration of BMSC to the bone resorption area and plays an important role in bone remodeling. Our previous study found that the level of active TGF-β1 in the bone marrow of mice with disuse osteoporosis was significantly increased, so the applicant proposed a hypothesis: TGF-β1 regulates coupling between bone resorption and formation by regulating BMSC migration, and TGF-β1 might be a potential target for disuse osteoporosis treatment. In this project, tail suspension method is to be used for mice disuse osteoporosis model construction, with which the role of TGF-β1 in regulating bone mass as well as bone resorption and formation coupling in mice is verified. GFP labelled BMSC is to be used for observing BMSC migration in mice with disuse osteoporosis. The activation of TGF-β1 and downstream signaling pathway is to be detected. The above experiments are all designed to clarify the mechanism of TGF-β1 regulated bone resorption and formation coupling in disuse osteoporosis.

废用性骨质疏松症是一种重要的继发性骨质疏松症类型，其高发病率与老龄化导致的长期卧床患者增加密切相关。废用性骨质疏松症表现为破骨亢进且成骨减低的破骨-成骨失耦联特征，然而其中的关键调控因子及调控机制仍缺乏明确报道。TGF-β1能够影响BMSC向骨吸收区域的迁移，在骨重建中发挥重要作用。课题组前期研究发现废用性骨质疏松症小鼠骨髓中活化TGF-β1水平明显升高，因此申请人提出假说： TGF-β1通过调节BMSC迁移来调控破骨-成骨耦联，是废用性骨质疏松症发病机制中的关键因子及潜在治疗靶点。本研究拟采用尾悬吊法构建小鼠废用性骨质疏松症模型，验证TGF-β1调控废用性骨质疏松症小鼠骨量及破骨-成骨耦联的作用，进而应用GFP标记的BMSC小鼠体内BMSC的迁移，并检测TGF-β1及下游信号通路的激活情况，以期阐明TGF-β1调控破骨-成骨耦联在废用性骨质疏松症中的作用及机制。

废用性骨质疏松症是一种重要的继发性骨质疏松症类型，其高发病率与老龄化导致的长期卧床患者增加密切相关。废用性骨质疏松症表现为破骨亢进且成骨减低的破骨-成骨失耦联特征，然而其中的关键调控因子及调控机制仍缺乏明确报道。TGF-β1能够影响BMSC向骨吸收区域的迁移，在骨重建中发挥重要作用。课题组前期研究发现废用性骨质疏松症小鼠骨髓中活化TGF-β1水平明显升高，因此申请人提出假说： TGF-β1通过调节BMSC迁移来调控破骨-成骨耦联，是废用性骨质疏松症发病机制中的关键因子及潜在治疗靶点。具体实施中，本项目研究内容分为三个部分：1）探究废用性骨质疏松症中的破骨/成骨失耦连现象：改进先有设施，发明“动物后肢废用性造模培养笼”，通过尾悬吊法构建小鼠废用性骨质疏松症模型，以HE染色、MicroCT评估小鼠骨量丢失，以病理切片染色及ELISA方法检测破骨/成骨标志物水平，明确废用性骨质疏松症与破骨-成骨失耦联密切相关。2）探究废用性骨质疏松症中破骨/成骨失耦连机制：检测活化TGF-β1 水平，并通过植入GFP标记的BMSC来追踪尾悬吊小鼠体内BMSC迁移情况，通过破骨细胞与成骨细胞染色，观察到破骨/成骨失耦连是由于TGF-β1过度活化导致BMSC无法向骨吸收区域迁移；3）明确TGF-β1作为靶点调控骨重建并治疗废用性骨质疏松症的应用价值：通过TβR1对小鼠废用性骨质疏松症的拯救实验，证实抑制TGF-β1 能够明显减轻废用性骨质丢失。本研究验证了TGF-β1调控废用性骨质疏松症小鼠骨量及破骨-成骨失耦连的作用，阐明TGF-β1过度活化影响BMSC正常迁移的机制，明确了TGF-β1作为靶点调控骨重建并治疗废用性骨质疏松症的应用价值。研究成果发表SCI论文6篇，核心期刊论文1篇，获得实用新型专利授权1项，培养了1名硕士研究生。