Figure 6. Endothelial cell response to TP activation as reflected by F-actin localization and content.

(A) Human pulmonary endothelial cells were treated with 75 or 150 nM of TXA₂ analogue (SQ 29548), and F-actin was localized by phalloidin staining. Images are representative of 3 experiments with similar results. Original magnification, ×175. (B) Activated platelets and activated PMNs induced a significant increase of F-actin formation in endothelial cells (n = 3 per group). The combination of stimulated platelets and PMNs caused a further increase of F-actin polymerization. ^ΧP < 0.05; ^#P < 0.05 versus control. (C) Platelet depletion with busulfan or TP antagonist SQ 29548 prior to induction of ALI led to significant prolongation of survival compared with that of HCl-treated mice (n = 4 per group). All mice treated with a P-selectin Ab survived until termination of the experiment (300 min), as did control mice (data not shown). The HCl group was significantly different from the other groups. P = 0.0002 by log rank test.