Evidence for the expression and enzymatic activity of haem oxygenase-1 in the lungs of horses.

This research study investigates the expression and activity of haem oxygenase-1 (HO-1), an enzyme, in the healthy lungs of horses. The study confirms that HO-1 is present and active within certain cells in the lung, and this activity can be influenced by certain factors.

Objective of the Research

• The main goal of this study was to examine the expression and the action of the haem oxygenase-1 (HO-1) enzyme in healthy horse lung tissue, and to measure the activity of this enzyme.

Research Methodology

• Lung tissue samples were obtained from six horses that were euthanised for reasons unrelated to any respiratory disorders.
• HO-1 expression and activity were examined in all samples. More specifically, type II alveolar epithelial cells, macrophages and neutrophils were under observation.

Key Findings

• The research confirmed that HO-1 is present and active in the cells of the horses’ lungs.
• The activity of HO-1 was observed to be dependent on the presence of NADPH, which is a reducing equivalent that helps in the functioning of many enzymes. Without NADPH, HO-1’s activity was affected.
• The researchers found that HO-1’s action can be inhibited competitively by adding increasing concentrations of a specific competitive inhibitor, tin mesoporphyrin IX. A competitive inhibitor is a substance that reduces an enzyme’s activity by competing for binding with the substrate.