Antioxidant and inflammatory responses of healthy horses and horses affected by recurrent airway obstruction to inhaled ozone.

Abstract

REASONS FOR PERFORMING STUDY:

Inhaled ozone can induce oxidative injury and airway inflammation. Horses affected by recurrent airway obstruction (RAO) have a decreased pulmonary antioxidant capacity, which may render them more susceptible to oxidative challenge. It is currently unknown whether RAO-affected horses are more susceptible to oxidative stress than those unaffected by RAO.

OBJECTIVES:

To determine whether ozone exposure induces greater oxidative stress and airway inflammation in RAO-affected horses in remission than in healthy horses.

METHODS:

Seven healthy control horses and 7 RAO-affected horses were exposed to 0.8 ppm ozone for 2 h at rest.

RESULTS:

At baseline, bronchoalveolar lavage fluid (BALF) ascorbic acid concentrations were lower in RAO-affected horses than healthy controls. Ozone appeared to preferentially oxidise glutathione rather than ascorbic acid 6 h after exposure. Individual healthy and RAO-affected horses demonstrated oxidation of BALF glutathione after ozone exposure. Overall, RAO-affected horses did not demonstrate increased oxidative stress following ozone exposure, compared with healthy horses. Ozone did not induce significant airway inflammation in either group.

CONCLUSIONS:

RAO-affected horses in remission are not more sensitive to ozone despite a decreased pulmonary antioxidant capacity. Sensitivity to ozone appears to be independent of initial pulmonary antioxidant status.

POTENTIAL RELEVANCE:

Horses with high susceptibility to oxidative stress may benefit from antioxidant supplementation.

• Authors: C M Deaton, D J Marlin, N C Smith, C A Roberts, P A Harris, R C Schroter, F J Kelly
• Journal: Equine veterinary journal (Equine Vet J) Vol. 37 Issue 3 Pg. 243-9 (May 2005) ISSN: 0425-1644 [Print] United States
• PMID: 15892234 (Publication Type: Journal Article)

Chemical References

• Antioxidants
• Oxidants, Photochemical
• Ozone
• Glutathione
• Ascorbic Acid

Topics

• Animals
• Antioxidants (analysis)
• Ascorbic Acid (analysis)
• Bronchoalveolar Lavage Fluid (chemistry, cytology)
• Case-Control Studies
• Female
• Glutathione (metabolism)
• Horse Diseases (chemically induced, metabolism)
• Horses (metabolism)
• Lung Diseases, Obstructive (metabolism, physiopathology, veterinary)
• Male
• Oxidants, Photochemical (adverse effects)
• Oxidation-Reduction
• Oxidative Stress (drug effects)
• Ozone (adverse effects)
• Recurrence