Abstract: AIM: To establish a mouse model of cy-tosine arabinoside (Ara-c) induced thrombocytopenia which leads inducement time more quickly and stably. METHODS: The mice were injected different dosages cytosine arabinoside (Ara-c)in two groups, respectively. The change of thrombocytopenia was observed in peripher-al hemogram and smear of marrow, andweightsof spleen, adrenal gland and thymus gland also were observed. RESULTS: The high dosage (200 mg°kg^-1)to the model formation was better than low dosage (100 mg°kg^-1)at inducement time and stability. The index showed no sig-nificant different between two groups except the volume of thrombocyte. CONCLUSION: Cytosine arabinoside-in-duced thrombocytopenia at high dosage (200 mg°kg^-1) can induce thrombocytopenia more effectively.

Key words: cytosine arabinoside (Ara-c), animal model, thrombocytopenia, megakaryocyte, immunosup-pression