miR-557 inhibitor increased the numbers of platelets and megakaryocytes and improved the symptoms of ITP. miR-557 inhibitor regulates apoptosis-related genes: Caspase-3 and Bax inhibition, and upregulation of bcl-2, p-Akt and p-ERK. This evidence concerns the gene CASP3 and autoimmune thrombocytopenic purpura.