No accumulation of desialylated platelets in the spleen, lung, or bone marrow. (A) Mice were i.v. injected with 50 mU sialidase, and platelet recruitment in the spleen (upper panel) and lung (lower panel) was investigated using SD-IVM. Representative images at the indicated time points after desialylation. Splenic red pulp macrophages, endothelial cells, and platelets were stained using anti-F4/80, anti-CD31, and anti-CD49b antibodies, respectively. Scale bars are 37 µm (top row) and 33 µm(bottom row). (B) Quantification of the accumulation of platelets in the spleen and lung upon desialylation. n = 3 mice. (C) Splenectomized (Spx) mice were treated with sialidase, and the platelet count was measured before and 24 h after treatment. n = 5 mice. (D and E) Mice were i.v. injected with ex vivo desialylated CellTracker-labeled platelets. 1 h later, the bone marrow was flushed out and analyzed. Flow cytometry shows no CellTracker signal in viable CD45⁺ CD11b⁺ F4/80⁺ bone marrow macrophages (D). Fluorescence microscopy shows no CellTracker signal in F4/80⁺ bone marrow macrophages. Scale bar is 51 µm (E). Unpaired two-tailed t test (C) was used to determine statistical significance. ***, P < 0.001. Results from all experiments shown are representative of at least three independent experiments.