Oxidative Versus Thrombotic Stimulation of Platelets Differentially activates Signalling Pathways.

INTRODUCTION Atherosclerosis is one of the inflammatory underlying disease associated by oxidative stress and thrombotic agents. This study aimed to evaluate the potential role of cupper oxidized low-density lipoprotein (OxLDL) and thrombin for inducing mitogen activated protein kinases (MAPKs) in platelets. METHODS Phosphorylation of P38MAPK, Jun N-terminal Kinase (JNK), and Extracellular signal-regulated kinases (ERK1/2) and P-selectin expression were determined in lysates of washed human platelets pretreated with low doses of thrombin and cu2+-OxLDL By Enzyme-linked immunosorbent assay (ELISA). Pharmacological inhibition was performed by SB203580, PD980559 and SP6000125 for P38MAPK, ERK1/2 and JNK activity, respectively. The ratio of phosphorylated to total protein was used for normalizing the phospho proteins contents of cells. RESULTS OxLDL and thrombin significantly and differentially increased P-selectin expression (P<0.05), P38MAPK (P<0.05) and c-JNK (P<0.05) and ERK1/2 (P<0.05) phosphorylation in platelets. SB 203580 and SP6000125 significantly decreased P-selectin expression in both oxidative (P<0.05) and thrombotic (P<0.05) activated platelets. CONCLUSION Our results indicated that MAPK inhibitors can reduce atherothrombotic events via alterations in P-selectin expression suggesting that these inhibitors may be useful in the inhibition of atheroma development.