Gelatinolytic activity in tracheal epithelial lining fluid and in blood from horses with chronic obstructive pulmonary disease.

Objectives: To determine whether gelatinolytic activity in tracheal epithelial lining fluid (TELF), blood neutrophils, and blood lymphocytes from horses was metalloprotease activity, and to compare, for healthy horses and horses with chronic obstructive pulmonary disease, gelatinolytic activity in neutrophils, lymphocytes, and serum with activity in TELF.

Animals: 7 horses with chronic obstructive pulmonary disease (COPD) and 4 healthy control horses.

Procedure: Neutrophils and lymphocytes were obtained by means of Percoll separation. Zymography was used to detect gelatinolytic activity; EDTA inhibition and 4-aminophenyl mercuric acetate activation were used to verify that gelatinolytic activity was metalloprotease activity.

Results: Gelatinolytic activity was significantly higher in TELF from horses with COPD than in TELF from healthy horses. For all samples, EDTA inhibited and APMA activated gelatinolytic activity. Gelatinolytic activity of neutrophils, lymphocytes, and serum was not significantly different between healthy horses and horses with COPD.

Conclusions: Results suggested that gelatinolytic activity in TELF from horses is metalloprotease activity. Gelatinolytic activity is increased in TELF from horses with COPD, but not in serum, neutrophils, or lymphocytes. Neutrophils and lymphocytes are possible sources of gelatinolytic activity in TELF.

Clinical Relevance: Measurements of serum, blood neutrophil, or blood lymphocyte gelatinolytic activity were of little value in distinguishing horses with COPD from healthy horses.