Effects of administration of ascorbic acid and low-dose hydrocortisone after infusion of sublethal doses of lipopolysaccharide to horses.
Authors: Anderson Melinda J, Ibrahim Alina S, Cooper Bruce R, Woolcock Andrew D, Moore George E, Taylor Sandra D
Journal: Journal of veterinary internal medicine
Summary
# Editorial Summary Endotoxaemia in horses triggers a systemic inflammatory response that depletes ascorbic acid and may impair the normal corticosteroid response to critical illness—phenomena well-documented in human sepsis but poorly understood in equine medicine. Anderson and colleagues administered sublethal lipopolysaccharide (LPS) to 32 healthy horses, then treated them one hour later with ascorbic acid, low-dose hydrocortisone, both agents combined, or placebo, measuring clinical signs, inflammatory markers, cytokine expression, and endocrine function at multiple time points. Whilst neither drug reduced pro-inflammatory cytokine production or clinical signs compared to controls, both agents independently preserved circulating neutrophil counts at critical time points—ascorbic acid maintained higher neutrophils at 6 hours post-LPS (11.01 K/μl versus 8.99 K/μl) and hydrocortisone at 12 hours (10.40 K/μl versus 6.88 K/μl)—suggesting protection against the neutropaenia that typically accompanies endotoxic shock. For practitioners managing endotoxaemic cases, these findings suggest that adjunctive ascorbic acid or low-dose hydrocortisone may help sustain neutrophil populations and potentially preserve innate immune function during the critical early phase of disease, though further clinical investigation in naturally occurring sepsis is warranted before definitive treatment protocols can be established.
Read the full abstract on PubMed
Practical Takeaways
- •In horses with endotoxemia, adjunctive treatment with ascorbic acid and/or low-dose hydrocortisone may help prevent neutrophil depletion, supporting immune function during critical illness
- •These treatments showed no adverse effects on inflammation markers and warrant consideration as part of multimodal endotoxemia management protocols
- •Early administration (within 1 hour) of these agents may optimize protective effects against sepsis-related neutropenia in clinical practice
Key Findings
- •Ascorbic acid administration was associated with higher blood neutrophil counts 6 hours after LPS infusion (11.01 K/μl vs 8.99 K/μL in controls, P<0.009)
- •Hydrocortisone administration was associated with higher blood neutrophil counts 12 hours after LPS infusion (10.40 K/μl vs 6.88 K/μL in controls, P<0.001)
- •Neither ascorbic acid nor hydrocortisone showed effects on clinical signs or pro-inflammatory cytokine gene expression compared to controls
- •Combined ascorbic acid and hydrocortisone therapy appeared to protect against LPS-induced neutrophil depletion