Role of selectins in experimental Staphylococcus aureus-induced arthritis

The selectin family of adhesion molecules mediates the initial attachment o f leukocytes to venular endothelial cells at sites of tissue injury and inf lammation. To assess the role of selectin family in Staphylococcus aureus-t riggered septic arthritis, we used several approaches. First, treatment wit h fucoidin, a carbohydrate molecule capable of binding to and blocking sele ctin functions, was used, in addition, we used P-selectin gene-targeted mic e as well as mice pretreated with monoclonal antibody blocking L-selectin f unction. The P-selectin-deficient and fucoidin-treated animals initially ex hibited a less severe septic arthritis both clinically and histopathologica lly. In the later stages of the disease no significant differences with res pect to arthritis were evident. Pretreatment with L-selectin blocking antib ody did not influence the severity of arthritis. High numbers of staphyloco cci were recovered from the kidneys of selectin-deficient mice, indicating a less efficient clearance of bacteria. Our results demonstrate a dual role for selectins in S. aureus-induced arthritis: on the one hand, blockade of these selectins leads to less severe arthritic lesions in the initial stag e of the disease; on the other, delayed recruitment of phagocytes decreases the clearance of bacteria.