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The Impact of Systemic Treatment With Flunixin Meglumine on the Two Antiproteases Alpha-2-Macroglobulin (A2M) and Alpha-1-Antitrypsin (A1AT) in Equine Plasma and Platelet-Rich Fibrin (PRF).
Abstract: To evaluate the effect of flunixin meglumine, a systemic non-steroidal anti-inflammatory drug (NSAID), on the antiproteases, A2M and A1AT, in equine plasma and PRF. Methods: A prospective cross-sectional study. Plasma, solid PRF, and liquid PRF were collected from a control-group that included healthy horses not treated with NSAIDs within the last 3 months. The NSAID-group were ophthalmology patients with no systemic inflammatory disease, and all received a full dose of flunixin meglumine (1.1 mg/kg BID PO or IV) for three or more days prior to collection. Samples were collected and prepared using a standardized protocol for plasma and PRF preparation. Concentrations of A2M and A1AT were analyzed with ELISA kits. Statistical analysis with Mann-Whitney U tests and Wilcoxon signed-rank tests was performed using significance set at p 0.05). Plasma had a significantly higher amount of A2M compared to solid and liquid PRF (both p < 0.001). Solid PRF had the highest concentration of A1AT and was significantly higher when compared to liquid PRF (p < 0.001), but not when compared to plasma (p = 0.071). Conclusions: The systemic NSAID, flunixin meglumine, does not appear to significantly alter antiprotease concentrations in equine plasma or PRF. Although PRF should not be used as a replacement for plasma, solid PRF may be a good adjunctive therapy for the treatment of keratomalacia due to its high A1AT concentration.
© 2026 The Author(s). Veterinary Ophthalmology published by Wiley Periodicals LLC on behalf of American College of Veterinary Ophthalmologists.
Publication Date: 2026-10-17 PubMed ID: 42888515PubMed Central: PMC13675482DOI: 10.1111/vop.70280Google Scholar: Lookup The Equine Research Bank provides access to a large database of publicly available scientific literature. Inclusion in the Research Bank does not imply endorsement of study methods or findings by Mad Barn.
- Journal Article
Summary
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Overview
- This study investigated whether systemic treatment with the NSAID flunixin meglumine affects the levels of two antiproteases, alpha-2-macroglobulin (A2M) and alpha-1-antitrypsin (A1AT), in horse plasma and platelet-rich fibrin (PRF).
- The researchers found that flunixin meglumine did not significantly change A2M or A1AT levels, but noted differences in concentrations between plasma, solid PRF, and liquid PRF, suggesting potential therapeutic uses of PRF.
Introduction and Purpose
- Flunixin meglumine is a systemic non-steroidal anti-inflammatory drug (NSAID) commonly used in horses to manage pain and inflammation.
- Alpha-2-macroglobulin (A2M) and alpha-1-antitrypsin (A1AT) are antiproteases that help regulate proteolytic enzymes and tissue degradation, potentially impacting healing processes.
- Platelet-rich fibrin (PRF) is a biological product derived from blood that contains platelets and fibrin matrix, used to promote tissue repair.
- The study aimed to evaluate whether systemic administration of flunixin meglumine affects the concentration of A2M and A1AT in equine plasma and PRF, which could influence therapeutic strategies.
Methods
- Design: Prospective cross-sectional study comparing two groups of horses.
- Control group: Healthy horses with no NSAID treatment for at least 3 months (n = 12).
- NSAID group: Horses receiving flunixin meglumine (1.1 mg/kg twice daily either orally or intravenously) for at least three days, but without systemic inflammatory disease (n = 12).
- Samples: Blood was collected and processed to produce plasma, solid PRF, and liquid PRF samples using a standardized protocol.
- Measurement: Concentrations of A2M and A1AT in the different blood products were quantified using enzyme-linked immunosorbent assay (ELISA) kits.
- Statistical analysis: Mann-Whitney U tests were used to compare groups; Wilcoxon signed-rank tests compared different blood products; significance threshold was p < 0.05.
Results
- No significant difference in concentrations of A2M or A1AT was found between the control horses and those treated with flunixin meglumine in any of the tested blood products.
- Plasma contained significantly higher amounts of A2M than both solid and liquid PRF (p < 0.001).
- Solid PRF had the highest concentration of A1AT, significantly greater than liquid PRF (p < 0.001), and tended to be higher than plasma though this was not statistically significant (p = 0.071).
Conclusions and Implications
- Systemic administration of the NSAID flunixin meglumine does not significantly alter the levels of key antiproteases A2M and A1AT in equine plasma or PRF.
- Since plasma contains more A2M, PRF should not be considered a substitute for plasma when antiprotease content is important.
- The high concentration of A1AT in solid PRF suggests it may have therapeutic benefits, particularly as adjunctive treatment for eye conditions like keratomalacia (corneal tissue degradation), where protease inhibition is beneficial.
- This study supports the potential use of PRF in equine ophthalmology but indicates that NSAID treatment with flunixin meglumine does not negatively impact antiprotease availability in plasma or PRF.
Cite This Article
APA
Scheunemann KR, Jones KEV, Young K, Zhang C, McGrath C, Love KR, de Linde Henriksen M.
(2026).
The Impact of Systemic Treatment With Flunixin Meglumine on the Two Antiproteases Alpha-2-Macroglobulin (A2M) and Alpha-1-Antitrypsin (A1AT) in Equine Plasma and Platelet-Rich Fibrin (PRF).
Vet Ophthalmol, 29(6), e70280.
https://doi.org/10.1111/vop.70280 Publication
Researcher Affiliations
- Department of Clinical Science, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
- Department of Clinical Science, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
- Department of Clinical Science, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
- Biobehavioral Laboratory, School of Nursing, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
- Biobehavioral Laboratory, School of Nursing, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
- KR Love Quantitative Consulting and Collaboration, Athens, Georgia, USA.
- Department of Clinical Science, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA.
MeSH Terms
- Animals
- Clonixin / analogs & derivatives
- Clonixin / pharmacology
- Clonixin / therapeutic use
- Horses / blood
- Anti-Inflammatory Agents, Non-Steroidal / pharmacology
- Anti-Inflammatory Agents, Non-Steroidal / therapeutic use
- Cross-Sectional Studies
- alpha-Macroglobulins / metabolism
- Female
- Prospective Studies
- Male
- Horse Diseases / drug therapy
Grant Funding
- T32 OD011130 / NIH HHS
- T320OD011130 / NIH HHS
Conflict of Interest Statement
The authors declare no conflicts of interest.
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