Evaled Expression of ICAM-1 and Its Ligands in the Rat Spinal Cord Following Lipopolysaccharide Intraspinal Injection

The early stage of inflammation involves the adhesion and transmigration of leukocytes across the blood–brain barrier (BBB) to the normally sequestered central nervous system (CNS). This process is regulated by the expression of a series of adhesion molecules. One of the most well-known components is intercellular adhesion molecule-1 (ICAM-1). It was described as a ligand of the membrane-bound integrin receptors lymphocyte function-associated antigen-1 (LFA-1) and monocyte adhesion molecules-1 (Mac-1) on leukocytes, and was involved in the adhesion and transmigration of leukocytes. Studies have demonstrated the upregulation of ICAM-1 in many tissues after lipopolysaccharide (LPS) stimulation, for example. In the CNS, recent studies just focus on the relatively acute effects in brain tissues, but neglected the possibly existed differences between the brain and the spinal cord following traumatic lesions. Our data demonstrated the upregulation of ICAM-1, LFA-1, and Mac-1 in the spinal cords of LPS intraspinal injected rats, and the location of ICAM-1 in microglia cells. These results suggested a possible role of this molecule in microglia-mediated immune response and antigen presenting in CNS immune diseases.