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Time‐related changes in equine neutrophils after experimental endotoxemia: myeloperoxidase staining, size, and numbers
Author(s) -
Lilliehöök Inger,
Tvedten Harold W.,
Bröjer Johan,
Edner Anna,
Nostell Katarina
Publication year - 2016
Publication title -
veterinary clinical pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.537
H-Index - 51
eISSN - 1939-165X
pISSN - 0275-6382
DOI - 10.1111/vcp.12334
Subject(s) - neutrophilia , myeloperoxidase , staining , medicine , absolute neutrophil count , neutrophile , granulocyte , inflammation , pathology , neutrophil extracellular traps , immunology , neutropenia , hematology analyzer , zymosan , andrology , biology , in vitro , biochemistry , toxicity
Background Neutrophil myeloperoxidase content is determined by the Advia 2120 hematology system by staining characteristics. Changes in myeloperoxidase staining are shown by location of neutrophils on Advia peroxidase dot plots and as myeloperoxidase index ( MPXI ). Significant changes in MPXI have been reported during severe inflammation in horses, dogs, and people but conclusions were inconsistent. Objectives Infusion of endotoxin was used to initiate an inflammatory stimulus under controlled conditions and over a longer time period than in previous studies to document kinetics of changes in neutrophil numbers, morphology, and myeloperoxidase staining. Identification of consistent time‐related changes may allow better interpretation of changes in neutrophil characteristics during inflammation. Materials Five Standardbred trotting horses received an intravenous infusion over a 6‐hour period with Escherichia coli endotoxin. Neutrophil count, MPXI , neutrophil characteristics in Advia 2120 Perox dot plots and neutrophil morphology in blood smears were monitored with repeated sampling for up to 10 days. Results Endotoxin infusion immediately caused severe neutropenia which converted to neutrophilia 14 hours after start of endotoxin infusion. Neutrophilia was still present 78 hours after start of infusion. Large “giant” neutrophils first appeared in blood smears and Advia Perox dot plots after 36–48 hours. A marked and consistent decrease in MPXI was seen in all horses 6 days (150 hours) after endotoxin exposure. Conclusions Endotoxemia caused prominent, time‐related changes in equine neutrophil characteristics including emergence of giant neutrophils and markedly decreased MPXI several days after endotoxin infusion.