Study On Apoptosis Of Myelodysplastic Syndrome Marrow Cells

Objectives:Myelodysplastic syndromes (MDS) are characterized by cytopenic peripheral blood, normo- or hyper-cellular bone marrow and frequent transformation into acute myeloid leukemia (AML). Well-regulated apoptosis is triggered by environmental factors and involved in oncogency of neoplasm. Tumor necrosis factor a inhibits hematopoiesis in vitro and in vivo. This study was to investigate apoptosis, its possible mechanism and causative factors of bone marrow cells in myelodysplastic syndromes (MDS) patients, as well as changes during the transformation of MDS into AML.Methods:Terminal deoxynucleotydyl transferase-mediated dUTP nick end labeling (TUNEL) was used to detect apoptosis of bone marrow mononuclear cells (BMNCs) from normal controls and patients with MDS, post-MDS AML and de novo AML. Percentages of apoptotic BMNCs from some of them were also evaluated by flow cytometry before and after having been cultured for 4 hours. Proteins bax and bcl-2 in BMNCs were determined by ABC cytoimmunochemi-cal assay. Serum tumor necrosis factor a (TNF-a) levels were measured with enzyme-linked immunosobinant assay (ELISA). Percentage of apoptotic BMNCs from one normal rib was quantified after having been cultured for 24 hours in medium containing 5% and 10% MDS or normal serum by flow cytometry and TUNEL.Results:1. Mean score ratio of bax/bcl-2 and percentage of apoptotic BMNCs were no difference statistically among MDS subtypes, as well as between MDS and post-MDS AML (p>0.05).2. Percentage of apoptotic BMNCs for MDS and post-MDS AML was higher than that for normal control and de novo AML (p<0.05), but not that detected by flow cytometry for post-MDS AML in comparison with de novo AML before BMNCs having been cultured (Oh) (p>0.05).3. Statistical differences of mean bax/bcl-2 score ratio were not found when MDS and post-MDS AML were compared to normal control and de novo AML (p>0.05).