Fig. 1

Impact of zoledronic acid (ZOL) on hematopoietic and peripheral blood cells. a Cohorts of C57BL/6 and nude mice (n = 5 per cohort per experiment × three experiments) were administered a single 100-μg/kg dose of ZOL or vehicle control (100 μl Hanks Balanced Salt Solution (HBSS)) via intraperitoneal injection and tissues were analyzed at indicated time points (red arrows) (b-d, f, g). b Number of hematopoietic stem cells (HSCs) per nude or C57BL/6 mouse femur at indicated time points after ZOL treatment, determined by flow cytometry using counting beads; **p = 0.003,*p = 0.04 (n = 15; 5 mice per cohort for each of three biological replications). c Bromodeoxyuridine (BrDU)-positive HSCs as a percentage of total HSCs per nude or C57BL/6 mouse femur; n.s. not significant; n = 10 femora (five mice, two femora per mouse). d Colony forming unit (CFU) assays using bone marrow cells (BMCs) isolated from both vehicle and ZOL-treated mice 3 (nude mice) or 5 days (C57BL/6 mice) after ZOL treatment. Colonies were counted 10 days later; nude mice *p = 0.04, C57BL/6 mice *p = 0.05. e BMCs from three naïve C57BL/6 mice and three nude mice were prepared in triplicate and subjected to CFU assay in the presence of 10 μM ZOL or 10 μL of 1X HBBS; colonies were counted after 10 days; n.s. not significant. f Representative Ki67 immunohistochemical stains of bone marrow from vehicle and ZOL-treated mice 5 days (C57BL/6) or 3 days (nude mice) after treatment (×40 objective). Quantification of Ki67 staining from indicated mice and time points. Colors indicate different biological replications; each data point represents an individual mouse for which an average of three different fields of view was calculated; nude mice *p < 0.0001, C57BL/6 mice **p = 0.0007. g Average fold change in bone marrow hematopoietic progenitor populations (HPCs) (quantified from one femur per mouse by flow cytometry; n = 5, representative of three biological replications) at indicated time points after one 100 μg/kg ZOL dose as compared to vehicle treatment. Ctl control, LT-HSCs long-term HSCs, ST-HSCs short-term HSCs, LSKs Lin-Sca1+cKit+, MPPs multipotent progenitor populations, CMPs common myeloid progenitors, MEPs megakaryocyte/erythroid progenitors, GMPs granulocyte/monocyte progenitors, LBPs lymphoid-biased progenitors, CLPs common lymphoid progenitors. Also see Table 1