For collecting BM fluids, the 2 femurs and 2 tibiae of each mouse were flushed with 200 μL of Hanks balanced salt solution/2% fetal bovine serum using a 0.3 mL insulin syringe with a 28-gauge needle and centrifuged at 500 × g for 5 minutes to remove the BM cells. The supernatants were further clarified by centrifugation at 12 000 × g for 10 minutes, and samples were subsequently stored at −80°C until use.29 (link) Cytokine levels were determined using the Proteome profiler array, mouse cytokine array panel A (R&D #ARY006) according to the manufacturer’s instructions. Each loaded sample was combined from 2 mice.