Effect of exercise on enzymatic activity in tracheal fluid and on intrapleural pressure difference in horses.

The study explores how exercise impacts the activity level of various enzymes in the respiratory fluid of horses and how it affects their intrapleural pressure difference. The research used seventeen trotters and took various readings before, during, and post workout. The findings noted changes in enzymatic activity and intrapleural pressure.

Methodology

• The researchers involved seventeen trotting horses in the study, out of which eight were healthy and nine bore mild respiratory diseases.
• These horses underwent a submaximal treadmill exercise while the researchers monitored certain metrics like their heart rate, breathing frequency, intrapleural pressure difference, haematocrit levels, as well as the concentration of lactic acid in the blood.
• Before and after the exercise, the scientists measured the activity level of beta-glucuronidase and plasmin, total proteolytic activity, and trypsin inhibitory capacity in the tracheal fluid of the horses.

Findings

• A significant increase in the Intrapericardial (IP) difference during exercise was notable. This returned to normal values within fifteen minutes post-workout for the healthy horses.
• No significant difference was observed in the intrapleural pressure between the healthy and diseased horses during the exercise.
• During the recovery period, an increase in the respiratory rate was observed, possibly driven by the respiratory compensation of the lactic acidosis caused by the exercise.
• Post-exercise, an increase in the activities of beta-glucuronidase was seen, whereas there was a decrease in the activities of plasmin and trypsin inhibitory capacity.
• The changes were most distinct in the decrease of plasmin activity.

Implications

• The total proteolytic activity in the tracheal fluid before exercise showed a correlation with the VLa4 values.
• The findings imply that mild respiratory diseases, which promote proteolysis (the breakdown of proteins into simpler molecules) in the respiratory tract, may decrease the performance capacity of horses.