Platelet counts and MKs adjacent to sinusoidal vessels in mice treated with or without VEGF and/or AMD3100. (A) Platelet counts in the ITP model mice. Platelet counts were lower in the ITP model group than in the control group (66 ± 28 × 10⁹/L vs 117 ± 43 ×10⁹/L, respectively; P < .05; n = 5). Visualization of MKs in BM sections from ITP mice (B-B′′′) or from control mice (C-C′′′) treated with PBS + PBS (B,C), VEGF-A₁₆₅ + PBS (B′,C′), AMD3100+PBS (B″,C″), or VEGF-A₁₆₅ + AMD3100 (B′′′,C′′′) (scale bars, 100 μm). (D) Data are expressed as mean ± SEM. (E) Circulating platelet numbers were enumerated 24 hours after the last growth factor administration. Data are expressed as mean ± SEM. n = 5 mice per group. *P < .01; **P < .001.