Assessment of leukotriene B4 production in leukocytes from horses with recurrent airway obstruction.
OBJECTIVE
To determine the ex vivo leukotriene (LT) biosynthesis in peripheral blood neutrophils (PBNs) and inflammatory cells in bronchoalveolar lavage fluid (BALF) obtained from horses affected with recurrent airway obstruction (RAO).


METHODS
6 RAO-affected and 6 control horses.


METHODS
Before and 6, 24, and 48 hours after stabling, disease severity was determined subjectively by clinical and mucus scores and measurement of the maximal change in pleural pressure (deltaPpl(max)); PBNs were isolated and BALF samples were examined cytologically. The PBN and BALF cells were activated with a calcium ionophore in the presence of arachidonic acid, and production of LTC4 and LTB4 was measured per 10(6) cells.


RESULTS
Clinical and mucus scores and deltaPpl(max) increased during stabling in RAO-affected horses, but not in control horses. In neutrophils and BALF cells from both groups, production of LTB4 exceeded that of LTC4. At all times, LTB4 production by PBNs was less in RAO-affected horses than it was in control horses. Before stabling, LTB4 production by cells in BALF was low in RAO-affected horses, but increased considerably after 6 hours of stabling. This increase coincided with the migration of neutrophils into the airways. In control horses, production of LTB4 did not change during stabling.


CONCLUSIONS
Results suggested increased production of LTB4 in airways of RAO-affected horses, compared with control horses, that may contribute to the infiltration of neutrophils into the lungs and the sustained inflammation associated with RAO.
Lindberg
Asa
A
Department of Medical Biochemistry and Biophysics, Division of Physiological Chemistry II, Karolinska Institutet, S-171 77 Stockholm, Sweden.
Robinson
N Edward
NE
Näsman-Glaser
Barbro
B
Jensen-Waern
Marianne
M
Lindgren
Jan Ake
JA
D000704:Analysis of Variance; D000818:Animals; D016718:Arachidonic Acid; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D002135:Calcium-Binding Proteins; D006734:Horse Diseases / Q000097:blood* / Q000378:metabolism; D006736:Horses; D007975:Leukotriene B4 / Q000096:biosynthesis* / Q000097:blood; D017997:Leukotriene C4 / Q000096:biosynthesis; D008173:Lung Diseases, Obstructive / Q000097:blood / Q000662:veterinary*; D009504:Neutrophils / Q000378:metabolism; D011312:Pressure; D013997:Time Factors
D002135:Calcium-Binding Proteins; C025673:calciphorin; D007975:Leukotriene B4; D016718:Arachidonic Acid; D017997:Leukotriene C4