Cytologic evaluation of bronchoalveolar lavage fluid from horses with recurrent airway obstruction after aerosol and parenteral administration of beclomethasone dipropionate and dexamethasone, respectively.
OBJECTIVE
To determine cytologic changes in horses with recurrent airway obstruction (heaves) after administration of aerosolized beclomethasone dipropionate and dexamethasone parenterally.


METHODS
6 horses with inducible and reversible heaves.


METHODS
Episodes of heaves were induced by exposure to moldy hay and straw for 7 days. Horses were assigned to treatment groups (aerosolized beclomethasone, parenterally administered dexamethasone, aerosolized propellant), and pulmonary inflammation was evaluated by serial cytologic examination of bronchoalveolar lavage (BAL) fluid samples obtained on days 0, 7, 10, 14, and 21. Total and differential cell counting and phenotypic analysis of lymphocyte subpopulations in BAL fluid were performed.


RESULTS
7 days of natural challenge induced neutrophilic inflammation. Neutrophil counts in BAL fluid were reduced in beclomethasone- and dexamethasone-treated horses on days 10 and 14 but rebounded to pretreatment values on day 21. The proportion of proinflammatory lymphocyte subpopulations (CD4+ and B+) and MHC class-II antigen expression were increased on days 14 and 21 in propellant-treated horses, compared with beclomethasone- and dexamethasone-treated horses.


CONCLUSIONS
Aerosolized beclomethasone attenuated neutrophilic pulmonary inflammation and prevented alteration in lymphocyte subpopulations in horses with heaves. Results were similar to the response associated with parenterally administered dexamethasone. Short-term administration of aerosolized beclomethasone without minimizing environmental allergen exposure is not expected to provide prolonged anti-inflammatory benefit for horses with heaves.
Department of Clinical Sciences, College of Veterinary Medicine, Kansas State University, Manhattan 66506-5606, USA.
B R
BR
Rush
M J
MJ
Flaminio
C J
CJ
Matson
J E
JE
Hakala
W
W
Shuman
D000280:Administration, Inhalation; D000336:Aerosols; D000402:Airway Obstruction / Q000188:drug therapy / Q000473:pathology / Q000662:veterinary*; D000821:Animal Feed; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000627:therapeutic use; D001507:Beclomethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D018893:Bronchoalveolar Lavage / Q000662:veterinary; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology* / Q000276:immunology; D018592:Cross-Over Studies; D003907:Dexamethasone / Q000008:administration & dosage / Q000627:therapeutic use*; D004311:Double-Blind Method; D005260:Female; D005516:Food Microbiology; D000949:Histocompatibility Antigens Class II / Q000032:analysis; D006734:Horse Diseases / Q000188:drug therapy* / Q000209:etiology / Q000473:pathology*; D006736:Horses; D007275:Injections, Intravenous; D008214:Lymphocytes / Q000276:immunology; D008297:Male; D012008:Recurrence
D000336:Aerosols; D000893:Anti-Inflammatory Agents; D000949:Histocompatibility Antigens Class II; D003907:Dexamethasone; D001507:Beclomethasone