表达可控的成骨特异性核心转录因子RUNX2联合音猬因子SHH骨髓内表达治疗骨质疏松症的实验性研究

Osteoporosis is the most common bone health problem, affecting millions of people all over the world. Bone marrow mesenchymal stem cells (BMSCs) are multipotent cells, which among other cell lineages, give rise to adipocytes and osteoblasts. It is hypothesized that the unbalance of BMSCs into adipocytes or osteoblasts may be a major cause of osteoporosis.In this study, we first intend to construct a regulated adeno-associated virus vector which carrying the RUNX2 gene of osteogenic molecular switch(AAV-RUNX2), then we transfect the "excess" adipocytes and BMSCs by above AAV in vitro, finally, we study the molecular pathogenesis of dynamic osteogenic/adipogenic balance by testing the osteogenic/ adipogenic-related gene expression in the AAV transfected cells. We also investigate the effects of Sonic Hedgehog on the balance of osteogenic/adipogenic balance. In the in vivo rat femoral model, we deliver a single injection of AAV-Runx2 and N-SHH protein directly into the bone marrow of the right femur in mature osteoporosis rats. In the medullary cavity, the AAV-Runx2 -mediated Runx2 overexpression induce the "excess" adipocytes trans-differentiate into osteoblasts so that we could direct "clear" excess intramedullary fat "junk" and to increase bone mass, and the gene expression during the process of the clearance is regulable. At last , by bone mineral density, biomechanical and bone histomorphometric testing to verify the efficacy of its treatment of osteoporosis.This experiment completion will further explore the molecular pathogenesis of osteoporosis, and it also provide a new method for the prevention and treatment of osteoporosis , and provide a stronger foundation to its potential clinical application.

骨质疏松是全球最重要的公共健康问题之一，具有很大的临床和经济意义。共同起源于骨髓基质干细胞（BMSCs）的成骨/成脂分化的动态失衡是导致骨质疏松的一个重要致病环节。本研究拟以髓腔内"过剩"的脂肪细胞和BMSCs为双靶点，构建表达可控、携带成骨分子开关RUNX2基因的腺相关病毒体载体，体外转染双靶点细胞，通过检测成骨/成脂相关基因的表达变化及Hedgehog信号通道音猬因子SHH对RUNX2调控的影响来探讨成骨/成脂转化的分子机制。RUNX2单独或联合SHH注射到骨质疏松大鼠骨髓腔内，通过髓腔内转染双靶点细胞促进"过剩"的脂肪细胞横向分化为成骨细胞，从而直接"清除"髓腔内多余的脂肪"垃圾"而增加骨量，并对"清除"的过程进行基因表达实时调控。通过骨密度、生物力学和骨组织形态计量学的检测来验证其治疗骨质疏松的疗效。课题的完成将进一步探讨骨质疏松症发病的分子机制，为骨质疏松症的防治提供一种新思路。

共同起源于骨髓基质干细胞（BMSCs）的成骨/成脂分化的动态失衡是导致骨质疏松的一个重要致病环节。本研究以髓腔内"过剩"的脂肪细胞和BMSCs为双靶点，采用携带成骨分子开关RUNX2基因的腺相关病毒体载体，体外转染双靶点细胞，通过检测成骨/成脂相关基因的表达变化可诱导成骨转化而抑制成脂；Hedgehog信号通道音猬因子SHH亦可抑制成脂肪作用和RUNX2有协同作用。RUNX2单独或联合SHH注射到骨质疏松大鼠骨髓腔内，通生物力学和骨组织形态计量学的检测该方法有较好的治疗骨质疏松的疗效。课题的完成探讨了骨质疏松症发病的分子机制，为骨质疏松症的防治提供一种新思路。