15d-PGJ2 enhances platelet production from mouse megakaryocytes in vitro. Bone marrow isolated from C57BL/6 mice was cultured for 5 days in the presence of rhTPO. On day 5 of culture, cells were treated with vehicle or 15d-PGJ2 (10 μM) for 24 hours. Cells were photographed in culture and platelet production was analyzed by flow cytometry. (A) Shown are the percentage of total cells from bone marrow cultures that are CD61+ platelets. Bone marrow cultures that were treated with either vehicle or 15d-PGJ2. Results are presented as mean plus or minus SD (P < .01). (B) Platelets were isolated from other cells in culture by gradient centrifugation from mouse bone marrow cultures treated with 15d-PGJ2. Left plot shows the forward and side scatter of untreated platelets. Right plot shows the forward and side scatter of platelets treated with collagen (10 μg/mL for 15 minutes). Note the decrease in size and increase in granularity. (C) Histogram showing the up-regulation of surface CD41 with collagen treatment. Values are a measure of geometric mean fluorescence intensity. (D) Scanning electron microscopy showing 2 culture-derived mouse platelets spread on a fibrinogen-coated slide. (E) Left picture shows microscopy of a mouse megakaryocyte cultured in the absence of 15d-PGJ2. Note the smooth surface. Right picture shows microscopy of a mouse megakaryocyte cultured in the presence of 15d-PGJ2. Note the ruffled surface, characteristic of morphologic changes that promote proplatelet formation.
