Equine studies
Outcome measures regarding disease-modifying changes were less common
but reported in four equine studies (Todhunter et al., 1998; Kay et al.,
2008; Kearney et al., 2021) and included synovial fluid (SF)
measurements (total protein [TP], cell counts, OA biomarkers,
glycosaminoglycans, and prostaglandin E2[PGE2]), histopathology of cartilage and synovial
membrane (SM), and measurements of protein synthesis and total
proteoglycans in cartilage.
In equine studies, TA showed improvements by decreasing SF TP, reducing
metalloproteinase (MMP) activity and chemokines (CCL2) (Kay et al.,
2008; Kearney et al., 2021); however, drawbacks such as increased
PGE2 SF concentrations were also found, was a transient
decrease in glycosaminoglycans (GAG) (Kearney et al., 2021). Results
regarding white blood cell (WBC) counts in SF were not consistent
between studies (Kay et al., 2008; Kearney et al., 2021).
MPA was evaluated in two equine studies, in which one found no
significant changes regarding SF, TP, cell counts, histopathology of
cartilage and SM, and proteoglycan (PG) and protein synthesis in
cartilage. However, increases in small PG were found by one author
(Todhunter et al., 1998), and suppression of matrix protein markers of
chondrocyte differentiation was found by another, which could be
associated with cartilage degeneration (Fubini et al., 2001).