COLLAGENOLYTIC ACTIVITY AND ITS SENSITIVITY TO DOXYCYCLINE INHIBITIONIN TRACHEAL ASPIRATES OF HORSES WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

The collagenolytic activity and its sensitivity to doxycycline inhibit ion in tracheal aspirates (TA) of horses with chronic obstructive pulm onary disease (COPD) was analyzed with SDS-PA gel electrophoresis (SDS -PAGE), using Type I collagen as the substrate. Both autoactive and to tal collagenase activities were significantly higher in TAs of horses with symptomatic COPD than in TAs of healthy horses. Doxycycline inhib ition studies suggest that most of the TA collagenase is of the neutro phil type (MMP-8), but some is derived from other cells such as fibrob lasts and monocyte/macrophages (MMP-1) and bacteria (bacterial collage nases). Drugs inhibiting collagenases in the respiratory tract might b e worth a trial in the treatment of COPD in horses.