Dimethylsulfoxide prevents chemoattractant-induced leukocyte adherence

The objective of this study was to determine whether dimethylsulfoxide (DMSO) influences chemoattractant-induced leukocyte adherence in the intestinal microcirculation. The distal colon of Sprague-Dawley rats was prepared for intravital microscopic observation of 25-35 microns diameter venules located in the muscularis externa. The number and average velocity of rolling leukocytes and the number of leukocytes adherent to the venular endothelial surface were determined from recorded video images. After a control period of observation, either N-formyl-methionyl-leucyl-phenylalanine (FMLP) or leukotriene B4 (LTB4) was added to the serosal superfusion solution. Both FMLP (1 microM) and LTB4 (1 microM) consistently caused leukocytes to adhere to venular endothelium. DMSO, at concentrations ranging between 2.5 and 140 mM, inhibited FMLP-induced leukocyte adherence in a dose-related manner. LTB4-induced leukocyte adherence was also significantly attenuated by DMSO. Leukocyte rolling velocity and leukocyte flux were not affected by DMSO. These results indicate that DMSO significantly inhibits leukocyte adherence at concentrations commonly used for its hydroxyl radical scavenging properties.