骨髓脂肪化是再生障碍性贫血(AA)患者骨髓最显著的病理特征之一。脂肪细胞是骨髓造血微环境中发挥负性调控作用的主要因素。成骨细胞在骨髓造血微环境中发挥促造血作用。骨髓脂肪细胞和成骨细胞的共同前体细胞是骨髓间充质干细胞（MSC）。通常情况下，骨髓MSC向脂肪细胞分化（成脂分化）和向成骨细胞分化（成骨分化）维持在一动态平衡水平。本研究拟在确认AA患者骨髓MSC成脂和成骨分化异常的基础上，利用流式细胞术、免疫印迹、免疫共沉淀、实时荧光定量PCR、功能分类基因芯片等研究手段，体外探讨三氧化二砷（ATO）调控、纠正AA患者骨髓MSC成脂与成骨分化失衡的有效性及分子机制。在此基础上，以小鼠AA疾病模型和AA患者为研究对象，利用流式细胞术、实时荧光定量PCR、造血干祖细胞体外克隆实验、骨髓活检及PET-CT等技术，体内初步探讨ATO联合环孢素治疗AA的有效性及作用机制, 为治疗AA探索新思路。

Aplastic anemia (AA) is characterized by a reduced number of hematopoietic cells and adipocytes replacement in the bone marrow. Studies suggest that bone marrow adipocytes are predominantly negative regulators of the bone marrow microenvironment, while osteoblasts promote a supportive environment for hematopoietic reconstitution. Adipocytes and osteoblasts originate from the common precursors, termed mesenchymal stem cells (MSC), within the bone marrow, where both display an inverse or reciprocal relationship. Generally, the adipogenic and osteogenic differentiation of MSCs maintains a dynamic balance in bone marrow. By flow cytometry, western blotting, co-immunoprecipitation analysis, quantitative realtime reverse transcriptase polymerase chain reaction, pathway-focused DNA microarray and so on, the present study was designed to investigate the efficiency and mechanisms of arsenic trioxide (ATO) in the regulation of the imbalance of adipogenic and osteogenic differentiation of MSC in patients with AA in vitro. After these, in order to create a novel therapeutic approach, we plan to use an established mouse model of AA and patients with AA to examine the efficiency and mechanisms of the combination of ATO and cyclosporine in the treatment of AA by flow cytometry, western blotting, quantitative realtime reverse transcriptase polymerase chain reaction, colony forming activity, bone marrow biopsy，PET-CT and so on.