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Inhalation of organic dusts and lipopolysaccharide increases gelatinolytic matrix metalloproteinases (MMPs) in the lungs of heaves horses
Author(s) -
NEVALAINEN M.,
RAULO S. M.,
BRAZIL T. J.,
PIRIE R. S.,
SORSA T.,
McGORUM B. C.,
MAISI P.
Publication year - 2002
Publication title -
equine veterinary journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.82
H-Index - 87
eISSN - 2042-3306
pISSN - 0425-1644
DOI - 10.2746/042516402776767277
Subject(s) - hay , matrix metalloproteinase , bronchoalveolar lavage , inhalation , horse , lipopolysaccharide , zymography , gelatinase , medicine , lung , chemistry , immunology , pathology , zoology , anesthesia , biology , paleontology
Summary We report the effects of mouldy hay/straw exposure, inhaled hay dust suspension (HDS) and inhaled lipopolysaccharide (LPS) on bronchoalveolar lavage fluid (BALF) gelatinolytic matrix metalloproteinase (MMP) levels and degree of activation in healthy (n = 6) and heaves‐ (previously termed chronic obstructive pulmonary disease) affected (n = 6 or 7) horses. Gelatinolytic MMPs in BALF were quantified by zymography, and gelatinases were shown by Western immunoblotting to be MMP‐2 and MMP‐9. Hay/straw and HDS challenges increased BALF total gelatinolytic activity only in heaves horses, with the majority of gelatinolytic activity comprising pro‐ and active MMP‐9. The 5 h duration hay/straw challenge increased BALF gelatinolytic MMP activity in heaves horses at 5 and 24 h after the start of this challenge, with activity returning to baseline by Day 4. In contrast to hay/straw and HDS challenges, LPS inhalation increased BALF gelatinolytic MMP activity in both groups. For all challenges, absolute BALF neutrophil counts were highly significantly correlated (P<0.0001) with levels of proMMP‐9 and active MMP‐9, but not with levels of MMP‐2 (P>0.05). As gelatinolytic MMPs are pro‐inflammatory agents, they may contribute to lung dysfunction and tissue destruction in heaves horses exposed to airborne organic stable dusts.