中文摘要：

目的研究骨髓增生异常综合征（MDS）患者骨髓间充质干细胞（MSC）的表型、分化功能和细胞遗传学特征，并通过分析MDS衍生的MSC（MDS—MSC）细胞遗传学异常的特征探讨MSC参与MDS发病及进展的可能机制。方法收集22例初诊MDS患者及7名正常对照者骨髓，通过贴壁培养体外分离扩增获得MSC。通过组化染色光镜下观察细胞形态学特征及利用流式细胞术检测表面抗原及成脂、成骨分化培养，初步分析其免疫表型特征及其多向分化潜能，进一步通过胰酶一Giemsa（GTG）显带技术分析MDS—MSC的细胞遗传学特征，并采用流式细胞术DNA定量分析方法证实相应结果。结果MDS—MSC保持细长纺锤形的形态学特征，表达CD73、CD90、CDl05等MSC相关抗原，不表达CD34、CD45等造血细胞的抗原特征，仍保持成脂、成骨分化功能。MDS—MSC的细胞遗传学异常率高（22例中有14例，64％），改变类型多样，其中以染色体物质缺失多见（93％），克隆性缺失占50％，此外发现2例患者染色体发生结构改变。MDS造血细胞异常核型组13例患者中12例（92％）检出MSC异常核型，高于MDS造血细胞正常核型组的33％（9例中检出3例）（P〈0．05）。造血细胞与MSC间没有出现完全一致的畸变类型，但是存在累及同一染色体却出现不同畸变类型的现象。结论MDS—MSC保持MSC原有表型特征和分化功能，但存在多种类型细胞遗传学畸变。染色体缺失可能是其遗传学不稳定的特征，缺失染色体相关基因单倍体剂量不足可能是MDS发病机制之一，MSC具有与造血细胞相似但不完全相同的遗传易感性，提示MSC在MDS发病机制中有潜在作用。

英文摘要：

Objective To investigate phenotype, cell differentiation and cytogenetic properties of bone marrow（BM） mesenchymal stem cells （MSC） separated from the myelodysplastic syndrome （MDS） pa- tients. And to analyze cytogenetic aberration of MSC derived from MDS （MDS-MSC） and its mechanism in pathogenesis of MDS. Methods Adherent MSC from both myelodysplastic （ n = 22） and normal （ n = 7） marrow were obtained by a stromal culture procedure. Morphological features were observed by optical micro- scope. The cell-surface antigens were performed by flow cytometer（FCM）. Adipogenic and osteogenic differ- entiation potential of MSC were identified under specific induction conditions. Standard cytogenetic analysis of both hematopoietic cells and MSC were performed by trypsin-Giemsa（GTG） banding. The karyotype analysis DNA content was determined by FCM to verify the results. Results The morphology of MDS-MSC was typi- cal slender spindle-shaped ceils, MSC obtained from MDS patients had a MSC immunophenotype, lacked the expression of hematopoietic antigens-CD34, CD45 and expressed MSC markers, such as CD73, CD90, and CD105. MDS-MSC layers showed the capability to differentiate towards adipocytes, chondrocytes and osteo- blasts. Cytogenetic aberrations were observed in MSC from 14 （64%） MDS patients, usually involve the loss of chromosomal material （92%） , and the clonal loss （7 cases, 50% ）. Two cases of structural aberrations were also detected. Abnormal karyotypes in MSC were still more frequently identified in abnormal hematopoi- etic cells ~roup （12 out of 13, 92% vs 3 out of 9, 33%, P 〈 0. 05） . There were not exactly the same type of chromosomal aberrations between hematopoietic cells and MSC, but different type of the aberrations in the same chromosome were involved. Conclusion MDS-MSC retains the phenotyping characteristics and differ- entiated function of normal MSC, but has different type of chromosomal abnormalities. A high proportion of loss of chromosomal may be a mar