IS increases platelet activity via ROS-induced activation of p38MAPK. (A) Flow cytometric analysis of the expression of P-p38MAPK in platelets of CKD mice after AST-120 treatment (n = 6). Data are mean ± SD. **P < .01 vs sham group; ^##P < .01 vs CKD group, ANOVA. (B) Flow cytometric analysis of the expression of P-p38MAPK in platelets of IS-treated mice (n = 6). Data are mean ± SD. **P < .01 vs vehicle group, Student t test. (C-D) Platelets were incubated with indicated concentrations of IS for 15 minutes. (C) Flow cytometric analysis of the expression of P-p38MAPK in platelets (n = 6). (D) Western blot analysis of the expression of P-p38MAPK and p38MAPK in platelets (i). Quantification of the ratio of P-p38MAPK/p38MAPK for each group (n = 3) (ii). (E-I) Platelets were pretreated with 5 mM NAC or 20 μM SB203580 for 15 minutes and then stimulated with 500 μM IS for another 15 minutes. (E) Western blot analysis of the expression of P-p38MAPK and p38MAPK in platelets (i). Quantification of the ratio of P-p38MAPK/p38MAPK for each group (n = 3) (ii). (F) Flow cytometric analysis of the expression of P-p38MAPK in platelets (n = 6). (G) Flow cytometric analysis of P-selectin expression in platelets in response to 2 μg/mL collagen (n = 6). (H) Flow cytometric analysis of the percentage of platelet-monocyte aggregates in response to 2 μg/mL collagen in vitro (n = 6). (I) Quantification of the area of platelet adhesion for each group (n = 6). (C-I) Data are mean ± SD. **P < .01 vs control or vehicle group; ^##P < .01 vs IS 500 μM group, ANOVA.