The efficacy of N-acetylcysteine in decreasing airway inflammation and mucus accumulation in horses with 18 hours of head confinement.
Authors: Tavanaeimanesh Hamid, Alinia Zahra, Sadeghian Chaleshtori Sirous, Moosavian Hamidreza, Mohebi Zeinab, Daneshi Mojtaba
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary: N-acetylcysteine reduces transport-related airway inflammation in horses Head confinement during transportation triggers significant airway inflammation and mucus accumulation in horses, conditions that can precipitate serious post-transport infection and compromise athletic performance; this 2024 study investigated whether N-acetylcysteine (NAC) supplementation could mitigate these pathological responses. Six healthy crossbred horses underwent a crossover protocol comparing four conditions: unrestricted movement (baseline), placebo with 18-hour head confinement, head confinement alone, and 15 mg/kg/day NAC administered orally for three days prior to 18-hour head confinement, with bronchoalveolar lavage (BAL) fluid analysis and endoscopic tracheal assessment performed in each condition. NAC treatment proved remarkably effective at preventing confinement-induced changes: confined horses without treatment showed total BAL cell counts of 34,291 cells/μL compared to 9,600 cells/μL in NAC-treated animals, whilst neutrophil percentages dropped from 53.8% (untreated confined) to 20.08% (NAC-treated), approaching baseline levels; endoscopic scores for mucus accumulation were significantly elevated only in confined untreated horses, with no difference between NAC-treated and unconfined horses. For equine practitioners managing transported horses—particularly competition animals, breeding stock, or those with pre-existing respiratory compromise—a three-day NAC course prior to transportation represents a practical, non-invasive intervention with strong evidence for suppressing the inflammatory cascade and mucociliary dysfunction that underpin post-transport respiratory disease.
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Practical Takeaways
- •Administer N-acetylcysteine at 15 mg/kg/day orally for 3 days before transportation to significantly reduce airway inflammation and mucus accumulation during 18+ hour head confinement events
- •NAC treatment restores normal inflammatory cell profiles in airways, reducing neutrophilic airway disease risk—a practical intervention for sport horse transporters
- •Consider NAC supplementation as a preventive strategy to reduce post-transportation respiratory complications and maintain performance careers in transported horses
Key Findings
- •NAC treatment significantly reduced endoscopic mucus scores compared to confined head without treatment (CH vs NAC, p<0.05)
- •BAL cell counts were significantly lower in NAC group (34,291±2,624 cells/μL in CH vs reduced in NAC)
- •Neutrophil percentage decreased from 53.8±8% in CH to 20.08±8% in NAC-treated horses
- •Macrophage percentage increased from 35.7±10% in CH to 66.33±9% in NAC-treated horses, indicating reduced inflammatory response