OBJECTIVE: To explore the mechanism of the impairment of hematopoietic stem/progenitor cells in aplastic anemia(AA) mice.METHODS: The hematopoietic cells from normal mice bone marrow were incubated with serum from AA mice in the presence of recombinant GM-CSF and IL-3. Parallel controls, i.e. hematopoietic cells from normal mice with or without serum of normal mice, were conducted. At different time, samples were collected and detected by flow cytometry (FACS), transmission electron microscopy (TEM) and gel electrophoresis.RESULTS: In the 16 post hour-culture of the experimental group mice: (i) The percentages of apoptotic cells were increased. (ii) Hematopoietic cells showed nuclear condensation, margination and blebbing under TEM. (iii) Agarose gel electrophoresis of DNA from the 13,000x g supernatant showed a ladder pattern. The percentage of DNA fragmentation measured by diphenylamine reaction was also increased and (iv) ZnSO4, cycloheximide and actinomycin D could partially suppress the induction of DNA fragmentation and delay the ocurrence of apoptosis.CONCLUSION: Apoptosis occurs in hematopoietic cells when incubated with serum from immune-mediated AA mice.
Anemia, Aplastic Animals