Equine Peripheral Gene Expression Changes in Response to Dose-Dependent Lipopolysaccharide-Induced Synovitis

Allen E. Page, Courtney Wood, Emma Partridge, David W. Horohov, Emma Adam

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


The use of lipopolysaccharide to induce a localized source of inflammation (acute synovitis) and allow for monitoring of changes in systemic mRNA expression has been recently reported. Here, the goal was to maintain a significant systemic mRNA response while limiting the severity of lameness such that this model can be used to examine the effects of various anti-inflammatory treatment modalities on mRNA expression. Three mixed breeds, four-year-old geldings were utilized for this study. One milliliter of phosphate-buffered saline containing 1,000 ng or less of lipopolysaccharide from E. coli O111:B4 was aseptically injected into alternating radiocarpal joints following washout periods. Blood for complete blood cell count, serum amyloid A concentration, and mRNA analysis via RT-qPCR for 23 different genes were collected before each injection, as well as at multiple times post-injection. Lameness severity was also graded at each time point. Two-way, repeated measures analysis of variance was used for statistical analysis (P < .05). Results largely replicated those previously reported, with multiple genes exhibiting significant expression changes during the acute inflammatory period (including increases in CD14, TLR4, IL-1β, IL1RN, MMP1, and MMP9 expression) while some demonstrated dose-dependent changes; significant increases in complete blood cell count parameters and serum amyloid A concentrations were also noted. Attempts to temper the severity of lameness were not successful as nonweight bearing lameness was noted at doses of 10ng or higher, while a dose of 1ng elicited neither a detectable lameness nor a significant change in mRNA expression.

Original languageEnglish
Article number103828
JournalJournal of Equine Veterinary Science
StatePublished - Feb 2022

Bibliographical note

Funding Information:
This project was funded by the Jes E. and Clementine M. Schlaikjer Endowment at the University of Kentucky. Funds from Lincoln Memorial University were used to pay the salary of Courtney Wood. SAA tests were provided by Zoetis who also paid for costs associated with CBC analysis.

Publisher Copyright:
© 2021 Elsevier Inc.


  • Horse
  • Inflammation
  • Lipopolysaccharide
  • Model
  • PCR

ASJC Scopus subject areas

  • Equine


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