NSAIDs are able to induce differentially the shedding of L-selectin in neutrophils.
(A) Surface expression of L-selectin (▪) and supernatant concentration of its soluble isoform (sL-selectin, ░) in neutrophils treated with different NSAIDs. Neutrophils isolated from peripheral blood were incubated for 30 minutes at 37°C in medium alone, with 20 ng/mL of PMA, or with 20 μg/mL of the different NSAIDs, except aspirin and sodium salicylate that were used at 200 μg/mL. After incubation, cell solutions were centrifuged, and supernatant fluids were tested for sL-selectin by an ELISA. Values were obtained in duplicate determinations for each sample. Data represent the mean (ng/106 cells) ± SD (░) from 3 independent experiments (left y axis). Simultaneously, the surface expression level of L-selectin in neutrophils was assessed by flow cytometry and expressed as the relative mean fluorescence (rMFI) as described in “Materials and methods.” Data represent the mean ± SD of rMFI (▪) from 5 independent experiments (right yaxis). PMA was used as positive control of L-selectin shedding. * = P < .05 and ** = P < .01 versus medium, by Student paired t test. (B) Graphical display of IC50 values of several NSAIDs on basal expression of L-selectin in neutrophils. Data were obtained from a representative dose-response experiment of 3.
