Thrombocytopoietic activity of rhIL-11 and JTZ-132 in myelosuppressed mice induced by busulfan. Changes of platelet (A,D), WBC (B,E), and RBC (C,F) numbers in mice that received busulfan. Busulfan was administered intraperitoneally with 2 sequential injections (15 mg/2.5 mL/kg) at day 0 and day 3. (A-C) Vehicle for rhIL-11 (0.1% BSA/saline, ○) or rhIL-11 (500 μg/kg/day, •), and (D-F) vehicle for JTZ-132 (0.02% Simulsol/5% glucose, ○) or JTZ-132 (7.5 mg/kg/d, •; 15 mg/kg/d, ▴;30 mg/kg/d, ▪) were administered subcutaneously from days 4 to 11. Heparinized blood was obtained from the sinus vein of the mice at indicated days, and the blood cell count was immediately measured by Sysmex F-800. Data represent mean ± SEM of 8 mice. Statistical analysis was performed by Student t test (# indicates P < .05; ##, P < .01) and Dunnett test (* indicates P < .05; **, P < .01) versus corresponding vehicle treatment.