GELATINOLYTIC ACTIVITY IN TRACHEAL ASPIRATES OF HORSES WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

The gelatinolytic activity in tracheal aspirates (TA) of horses with c hronic obstructive pulmonary disease (COPD) was analyzed using SDS-PAG E-gelatin-gel electrophoresis (zymography) and compared to TAs from he althy controls. The 110-90 kD MMP-9 type gelatinase was high in sympto matic disease phases (permanent disease 0.46 +/- 0.15, p<0.001; or int ermittent disease 0.47 +/- 0.12, p<0.001) compared to healthy controls (0.10 +/- 0.07). Similarly, the overall gelatinolytic activity, the a ctivity in high-mw gelatinolytic bands (210-190 and 150 kD) and in pro teolytically processed fragments in the 50-40 kD range were high, wher eas the 75-65 kD MMP-2 was not altered. These findings suggest that MM P-9 type gelatinases, originating possibly from neutrophils or macroph ages, and products thereof have a role in the pathogenesis of equine r espiratory diseases, whereas MMP-2 type gelatinases represent house-ke eping proteinases involved with normal tissue remodelling. The gelatin olytic activity in TAs correlated with the beta-glucuronidase activity , which indicates that they are simultaneously elevated in the respira tory secretions of horses suffering from COPD and might both be of sam e origin, or have a causal relationship.