REGULATION OF E-SELECTIN, P-SELECTIN, AND INTERCELLULAR-ADHESION MOLECULE-1 EXPRESSION IN MOUSE CREMASTER MUSCLE VASCULATURE

Objective: To investigate the expression of P-and E-selectin and inter cellular adhesion molecule 1 (ICAM-1) in the vasculature of mouse crem aster muscles both with and without tumor necrosis factor alpha (TNF-a lpha) treatment. Methods: Mice received injections of monoclonal antib ody to P-selectin, E-selectin, or ICAM-1 before fixation to restrict d etection to antigen expressed on the endothelial surface. Whole-mount preparations of mouse cremaster muscles ere fixed in acetone and stain ed using biotinylated secondary antibody and perxoidase-conjugated str eptavidin. Results: P-selectin is expressed on the endothelial surface of cremaster muscle venules within 10 minutes after exteriorization. Expression increases upon treatment with TNF-alpha (2 hours): reflecti ng transcriptional relation of P-selectin expression in situ. Tile bas eline E-selectin expression is patchy and barely detectable but shows a significant upregulation after treatment with TNF-alpha. ICAM-1 is c onstitutively expressed in unstimulated mouse cremaster venules and sl ightly upregulated after 2 hours of TNF-alpha treatment. Under baselin e conditions, neither E-selectin, P-selectin. nor ICAM-1 is detectable in arterioles or capillaries. After TNF-alpha treatment, arterioles s tain faintly for P-selectin, but not E-selectin or ICAM-1. Conclusion: The temporal and spatial pattern of expression of P-and E-selectin an d ICAM-1 is consistent with the functional role of these molecules in mediating preferential leukocyte rolling and adhesion in mouse cremast er muscle venules.