TXA2 mediates release of Endostatin from platelets. (A) Immunofluorescence of platelets (plts) activated with TXA2 (100μM) and labeled with VEGF (red) and endostatin (green). Scale bar is 2μm in size. (B) Number of granules labeled with VEGF, endostatin, or VEGF and endostatin, in resting platelets or platelets incubated with TXA2. Numbers represent average granule counts from immunofluorescence images. (C) Endostatin concentration in the releasate of resting platelets or platelets activated with TXA2 or PAR4. (D) VEGF concentration in releasate generated from platelets resting or activated with TXA2 or ADP. (E) Endostatin concentration in the releasate generated from platelets activated with various concentrations of TXA2. (F) Endostatin concentration in the releasate generated from platelets pretreated with TXA2 antagonist before exposure to TXA2. * indicates P < .05.
