The in vivo effect of a therapeutic dose of prednisolone on canine neutrophil adherence, random migration, chemotaxis, phagocytosis of IgG and C3b opsonized yeast cells, chemiluminescence, Fc- and CR3-receptor expression was investigated. Prednisolone was also added in vitro to neutrophils as isolated cells and in whole blood. In the in vivo study, prednisolone increased the IgG mediated ingestion of yeast cells and the number of activated neutrophils in the phagocytosis assay, while flow cytometric investigation of the IgG-receptor Fc gamma RIII with a monoclonal antibody showed similar expression before, during and after treatment. Prednisolone also increased the ingestion of C3b-opsonized yeast cells, while the expression of CR3-receptors (CD11b CD18) measured by flow cytometry was unchanged. Chemiluminescence and the chemotactic response towards zymosan activated serum were increased, while adherence to nylon wool was decreased. The in vitro studies revealed that prednisolone had no or a dampening effect on neutrophils in cell suspensions. Adherence as well as IgG mediated ingestion was decreased at the highest prednisolone concentration (800 ng/ml) in whole blood. The present study suggests that the part of the antiinflammatory effect of corticosteroids mediated through their influence on neutrophils, besides reduced adherence, may be exerted by increased clearance of microorganisms and IgG-complexes through an elevated functional capacity.
I föreliggande studie undersöktes in vivo-effekten av en terapeutisk dos prednisolon på neutrofilers adhesion, migration/kemotaxis, fagocytos och chemiluminescence hos hund. Prednisolonets påverkan på antalet FcγIII-receptorn och CR3-receptorer studerades också. Prednisolon tillsattes även in vitro till neutrofilsuspension och effekten på neutrofilernas funktion studerades. Resultaten visar att det föreligger skillnader mellan effekten av prednisolon in vivo och in vitro. När prednisolon gavs in vivo, minskade neutrofilernas adhesion och den fagocyterande och avdödande förmågan ökade. Antalet Fc- och CR3-receptorer påverkades inte av behandlingen. När prednisolonet tillsattes in vitro till cellsuspensioner hade det ingen eller dämpande effekt på neutrofilerna.
Resultaten tyder på att en del av den antiinflammatoriska effekten vid kortisonterapi in vivo, förutom den minskade adhesiviteten, kan vara ökad eliminering av mikroorganismer och IgG-komplex genom ökad kapacitet hos neutrofilerna.