IL-1α inhibited regulated tubulin assembly and proplatelet formation. (A) Quantification of MK numbers and dynamics and platelet counts in 6-wk-old CAG-eGFP mice treated with IL-1α (10 µg for 5 d), colchicine (5 mg/kg i.v. once 6 h before experiments), and/or paclitaxel (10 mg/kg i.v. once 6 h before experiments). The BM was visualized and platelet counts were analyzed 7 d after the first administration. n = 24 high-power fields from 8 animals in each group. *, P < 0.05 versus control (WT) (B–D) Immunofluorescence analysis of fetal liver MKs cultured and differentiated from day 0 to 7 with TPO or IL-1α. In addition, the cells were treated with colchicine (2.5 µM) or paclitaxel (2.5 µM) from day 6 to day 7 (B). Some cells were also treated with Fas-ligand with TPO from day 6 to 7 (FasL). On day 7, the cells were fixed and stained (C and D). (E) RT-PCR analysis of gene expression in harvested cells. The values were normalized to vehicle-treated control. n = 8 experiments. (F) Electron microscopy of isolated BM MKs from TPO or IL-1α mice. Note that demarcation membrane system was similarly developed in two mice (1 and 2), before rupture, and fragments indicated several platelets (3 and 4). Bars, 2 µm. (G) Immunofluorescence study of tubulin distribution in platelets from WT, Thpo^−/− mice, or Thpo^−/− mice treated with IL-1α. (H) Electron microscopy of isolated platelets from WT mice treated with vehicle (WT), TPO, or IL-1α. (I) The short and long axis length was measured in randomly selected individual platelets, and ratio (short/long) was evaluated in 40 cells for each groups. Bars, 2 µm. *, P < 0.05.