Systemic alteration of BM progenitor and myeloid cells in c-fms-rtTA/(TetO)7-CMV-MMP12 bitransgenic mice. (A) Representative flow cytometric profiles of BM progenitor populations, including CMPs, MEPs, and GMPs, from 3-month doxycycline-treated (+DOX) or untreated (−DOX) bitransgenic mice. (B) The percentages and total numbers of LSK, LK, CMP, MEP, and GMP populations in the BM of 3-month doxycycline-treated (+DOX) or untreated (−DOX) bitransgenic mice. Results are the mean ± SD, n = 4; *P < .05. LK indicates IL7Rα−Lin−c-Kit+Sca-1− progenitor; LSK, IL7Rα−Lin−Sca-1+c-Kit+ progenitor; CMP, common myeloid progenitor; GMP, granulocyte-monocyte progenitor; and MEP, megakaryocyte-erythroid progenitor. (C) Granulocyte colony formation in 5 × 104 BM cells from doxycycline-treated (+DOX) or untreated (−DOX) bitransgenic mice in methylcellulose containing various concentrations of G-CSF. Colony counts were performed at day 10. Results are the mean of 5 independent studies, n = 5. (D) A representative flow cytometric analysis of CD11b+ and GR-1+ cells in the BM and spleen of 3-month doxycycline-treated wild-type (WT) mice, doxycycline-treated (+DOX) bitransgenic mice, doxycycline-untreated (−DOX) bitransgenic mice, and doxycycline-treated (for 2 months) followed by doxycycline-removal (for 1 month) bitransgenic mice. (E) Absolute cell numbers of CD11b+/GR-1+ cells in the BM and spleen based on analyses of the above experimental groups. Results are the mean ± SD, n = 5; *P < .05.