Antibodies to PECAM-1 and glucocorticoids reduce leukocyte adhesion in adjuvant arthritis of the rat knee synovium in vivo.

Abstract

To demonstrate the effect of monoclonal antibodies to the adhesion-molecule PECAM-1 (CD31) and of prednisolone on leukocyte adhesion in rat adjuvant arthritis. Adjuvant arthritis was induced in male CD-rats (five groups of n = 6) 18 days prior to measurements. Mouse-monoclonal antibody to rat CD-31 at 200 microg/kg or prednisolone at 24 mg/kg were administered i.v. 15 minutes prior to measurements. Venules within the intact rat-knee synovium were focused by confocal laser scanning microscopy. Numbers of rolling and adherent leukocytes were assessed in vivo. Induction of arthritis significantly increased rolling and adherent leukocytes compared to healthy controls. Both monoclonal antibodies to PECAM-1 and prednisolone significantly reduced adherent, but not rolling leukocytes in arthritic animals. The method used is well suited for in vivo quantification of leukocyte adhesion under the influence of antiadhesive therapies. PECAM-1 might be an interesting target for novel therapies in rheumatoid arthritis.