骨髓间充质干细胞移植在染矽尘大鼠体内归巢与分化的研究

Pneumoconiosis is the number one occupational disease in our country. Half of pneumoconiosis is silicosis，but it still hasn't effective treatment. Mesenchymal stem cells （MSCs）are a population of multipotent cells. Some studies reported MSCs can relieve the damage of lung induced by bleomycin and radiation. Clinical trails also showed MSCs were safe. Our early study found MSCs seemed to have protective effect on lung injury induced by silica. But it needs more experiments to support. We design intravital and intracorporal synchronous tracking of bone mesenchymal stem cells of labeled with superparamagnetic ironoxide(SPIO) by magnetic resonance imaging(MRI) and microscopy in rats injured by silica, detection of characteristic protein expression of rat lung tissue cells after non-contacting co-culture with MSCs by laser scanning confocal microscope，gene expression of cells by RT-PCR. We will study MSCs'homing and differentiation in rats injured by silica from animal, cell and numerator level, and completely evaluate the repair effection of MSCs on lung injury by silica. It will provide exprimental date of MSCs treatment to silicosis.

尘肺是我国头号职业病，矽肺又占其中一半，但至今缺乏有效疗法。间充质干细胞（MSCs）有强大的多向分化潜能，有报道MSCs能减轻博来霉素、放射等所致肺损伤，其安全性也经过临床试验证明，均为MSCs治疗矽肺提供了良好的理论基础。我们前期发现骨髓MSCs可能极具对矽尘致肺损伤修复的潜力，但未深入研究。本研究拟将超顺磁性纳米氧化铁颗粒(SPIO)标记的骨髓MSCs移植至染矽尘大鼠体内，通过磁共振成像和显微技术进行活体和体内同步示踪；并将染矽尘大鼠肺组织细胞与MSCs非接触共培养后，用激光共聚焦显微镜检测不同肺组织细胞标志蛋白的表达，RT-PCR检测其基因的表达，从动物、细胞、分子水平多层次观察MSCs在染矽尘大鼠体内的归巢、分化能力。同时从大鼠生长状况、肺泡炎症、纤维增殖情况多方位全面评估MSCs对矽尘致肺损伤的修复作用。为MSCs移植治疗矽肺提供实验依据，并可推动活体水平对MSCs移植的监测。

尘肺为我国患者人数最多的职业病，约占职业病的九成，其中矽肺近半，但一直缺乏有效治疗方法。间充质干细胞（MSC）能减轻多种因素引起的肺部炎症、肺纤维化，但能否对矽尘所致肺损伤存在修复作用尚未知。本研究从动物、组织、细胞、分子等不同层次对实验大鼠整体、肺部炎症、肺纤维化进行评估，发现MSCs能减轻染矽尘大鼠肺部炎症及肺纤维化，提示MSCs对矽尘所致肺损伤存在修复作用。将慢病毒载体介导的增强型绿色荧光蛋白（Lv-eGFP）转染的骨髓MSCs移植至染矽尘大鼠体内，通过荧光显微技术进行体内动态示踪，发现MSCs在染矽尘大鼠体内可归巢到受损的肺部。再将MSCs与染矽尘大鼠的肺泡上皮细胞(AEC)非接触共培养后，激光共聚焦显微镜检测MSCs是否表达AECⅠ、Ⅱ标志蛋白AQP5、SP-C，RT-PCR检测其基因的表达，结果提示染矽尘AEC能有效诱导 MSCs分化为AEC。本研究为MSCs治疗尘肺提供了动物实验依据，对尘肺治疗新方法有指导意义。