Authors
, , , , , and
Abstract
Objective—To evaluate lipopolysaccharide (LPS)- induced activation of equine neutrophils in blood.
Sample Population—Blood samples from 5 healthy adult Thoroughbreds.
Procedure—Neutrophil integrin (CD11/CD18) expression, size variation, degranulation, and deformability were measured with and without incubation with LPS. Time and concentration studies were done. The mechanism of endotoxin-induced neutrophil activation was investigated by inactivating complement or preincubating neutrophils with inhibitors of tumor necrosis factor-α (TNF-α) synthesis, prostaglandin-leukotriene synthesis, or plateletactivating factor.
Results—Incubation of equine neutrophils with LPS increased cell surface expression of CD11/CD18, decreased neutrophil deformability, increased and decreased neutrophil size, and induced neutrophil degranulation. The LPS-induced neutrophil activation was attenuated by addition of inhibitors of TNF-α and prostaglandin-leukotriene synthesis.
Conclusion and Clinical Relevance—Equine neutrophils are readily activated in vitro by LPS, resulting in increased expression of integrin adhesion molecules, decreased deformability, variation in neutrophil size, and degranulation. The tests used to detect activated neutrophils in this study may be useful in detecting in vivo neutrophil activation in horses with sepsis and endotoxemia. (Am J Vet Res 2002;63:811–815)
