Osteoclast impaired mice as donors or recipients in transplantation settings. (A) CD45.2 BM cells from control or ALN-treated mice were mixed with equal amounts of CD45.1 competitor BM cells and transplanted into lethally irradiated CD45.2/CD45.1 recipients. The percentage of CD45.2⁺ cells was then determined into the PB of recipient mice by FACS analysis at regular time intervals. (B) BM cells from ALN-injected mice had impaired ability to reconstitute in the long-term lethally irradiated recipients as shown by flow cytometry for CD45.2. Columns represent mean ± SEM; n = 6 in each group. *P < .05. **P < .01. (C) Recipient mice that received 4 weekly injections of ALN before γ-irradiation with 13 cGy were reconstituted with 4 × 10⁶ BM cells. An untreated group was used as controls, and the engraftment was monitored by blood enumeration at regular time intervals. (D) ALN-injected mice had reduced numbers of (i) white blood cells and (ii) platelets (PLT) within the first 4 weeks after transplantation. Data are mean ± SEM; n = 8. *P < .05. **P < .01. ns indicates not significant. (E) ALN pretreated recipients fully recover 16 weeks after transplantation because they exhibited comparable frequencies of CFU-C and (F) LKSFlk2⁻ cells in the BM population to the untreated controls. Data are mean ± SEM; n = 8.