Objective: To investigate the change of autophagy level of bone marrow mononuclear cells（BMMNCs）in patients with myelodysplastic syndromes（MDS）.
Methods: Thirty- eight patients with MDS and 26 megaloblastic anemia patients were enrolled in this study. The autophagic vacuoles were observed by transmission electron microscopy （TEM） and the quantity of autophagic vacuoles was detected by monodansylcadaverine （MDC） staining. The LC3 protein positive cells were counted by immunofluorescence assays. The expression of Beclin 1, LC3A, mTOR mRNA were measured by real time PCR. The expression of Beclin 1 proteins were detected by Western blotting.
Results: The autophgic vacuoles of double membrane that surrounds lysosomes appeared in MDS patients. The percentage of MDC positive cells was significantly higher in MDS patients［（9.75±2.63）%］than that of controls［（2.90± 0.89）%, P＜0.05）. The percentage of LC3 protein cells was also increased in MDS patients（6.13±1.03）% vs（1.5±0.58）%, P＜0.05）. The expression of Beclin 1 and LC3A mRNA in low-risk and intermediate-1 MDS were higher compared with controls （3.61 ± 3.02 vs 1.55 ± 1.03 and 6.56 ± 3.97 vs 1.21 ± 0.95 respectively, both P＜0.05）. The expression of mTOR mRNA was down- regulated in low- risk and intermediate-1 MDS compared with controls（0.39±0.37 vs 1.50±1.03, P＜0.05）. There were no significant difference in expression of Beclin 1, LC3 and mTOR mRNA among intermediate-2 and high-risk MDS and controls. Beclin 1 protein expression was higher in low- risk and intermediate- 1 MDS patients（1.257 ± 0.197）than that of controls（0.528±0.086）and inermediate-2 and high-risk MDS patients（0.622±0.118）.
Conclusion: The autophagy levels were increased in low- risk and intermediate- 1 MDS, while not enhanced in intermediate-2 MDS. Autophagy might be considered as a cell protective mechanism in MDS. The relatively defective autophagy in intermediate- 2 and high- risk MDS might contribute to disease's progression.
目的: 研究骨髓增生异常综合征（MDS）患者骨髓单个核细胞（BMMNC）自噬水平的变化，探讨细胞自噬在MDS中的作用。
方法: 以38例MDS患者为实验组，以26例巨幼细胞贫血患者为对照组，抽取骨髓并分离BMMNC。应用透射电镜观察自噬情况；采用单丹（磺）酰戊二胺（MDC）染色法检测自噬泡水平；采用RT-PCR、免疫荧光技术及蛋白免疫印迹法检测微管相关蛋白轻链3（LC3）、Beclin1 mRNA及蛋白的表达水平。
结果: MDS患者BMMNC内易见自噬泡；MDC染色显示MDS患者BMMNC含自噬泡细胞数量显著高于对照组[（9.75±2.63）%对（2.90±0.89）%，P<0.05]；MDS患者BMMNC LC3阳性细胞比例显著高于对照组[（6.13±1.03）%对（1.50±0.58）%，P<0.05]。低危/中危-1 MDS患者BMMNC Beclin1及LC3A mRNA表达水平显著高于对照组（3.61±3.02对1.55±1.03，P<0.05；6.56±3.97对1.21±0.95，P<0.05）；低危/中危-1 MDS患者BMMNC自噬负性调控基因-哺乳动物雷帕霉素靶点（mTOR）mRNA水平显著低于对照组（0.39±0.37对1.50±1.03，P<0.05）；中危-2/高危MDS患者BMMNC Beclin1、LC3和mTOR mRNA表达水平与对照组比较差异均无统计学意义（P值均>0.05）。蛋白免疫印迹法显示低危/中危-1患者BMMNC Beclin1蛋白表达（1.257±0.197）高于对照组（0.528±0.086）及中危-2/高危（0.622±0.118），差异均有统计学意义（P<0.05）。中危-2/高危组和对照组比较差异无统计学意义（P>0.05）。
结论: 低危/中危-1 MDS患者BMMNC自噬水平升高，中危-2/高危MDS组患者BMMNC自噬水平无明显改变，自噬对MDS患者可能起保护性作用，自噬水平相对不足可能与MDS的进展有关。