NPR and PR platelets attenuate thrombin-induced disruption of adherens and tight junctions. (A) Treatment with NPR or PR platelets lessened the loss of endothelial junctional proteins in response to thrombin challenge. HUVEC monolayers were stained for VE-cadherin (green), F-actin with phalloidin (red), and DAPI (4′,6-diamidino-2-phenylindole; blue) in images 1, 3, 5, and 7 as well as ZO-1 (white) in images 2, 4, 6, and 8. White arrows highlight gaps between endothelial cells. Platelets from trials 2 and 3 were tested on days 3, 5, 7, and 10, and representative images from trial 2, day 5 are shown. (B) Quantified gap measurement was significantly less in day 3 NPR platelets (orange) compared with PR platelets (blue), but that difference was not maintained as the platelets aged. In addition, there was an increase in gap size between cells with thrombin alone compared with control and a statistically significant decrease with both treatment of NPR and PR platelets. Differences were calculated with 2-way ANOVA. ∗P < .05. ns, nonsignificance.