Increased level of inflammatory cytokines in irradiated BM cells. (A) Cytokine antibody array analysis of irradiated and nonirradiated BM cells. Cell lysates of BM cells were collected from 10 Gy IR mice (n = 3) and NR mice 17 hours after treatment. Cell lysates were sent for membrane-based mouse cytokine antibody array. The cytokines increased more than 2-fold in irradiated cells compared with nonirradiated controls. Lower panels: Representative membrane image. (B) Increased level of activated MMP9 in irradiated BM cells. Cell lysates were also used for activated MMP9 measurement using ELISA. The fold change in irradiated BM compared with nonirradiated BM lysates is shown based on 3 experiments. (C) Down-regulation of c-Kit expression. C-kit-enriched BM cells were injected into lethally IR or NR MMP9^+/+ or MMP9^−/− mice, respectively. Mice were killed at 17 hours after transplantation, and the expression of c-Kit in the donor cells was measured by flow cytometry. Panels represent the representative flow charts gated in the donor Lin⁻ cells.