Interleukin-1β and methylprednisolone acetate demonstrate differential effects on equine deep digital flexor tendon and navicular bone fibrocartilage cells in vitro.

The research is about the study of the effects of Interleukin-1β (IL-1β) and methylprednisolone acetate (MPA) on equine intrabursal deep digital flexor tendon (DDFT) and navicular bone fibrocartilage (NBF) cells. The findings reveal that NBF cells are more impacted by IL-1β and MPA, which could inform future treatment regimens for horses with navicular disease.

Study Methodology

• The study involved third passage DDFT and NBF cells which were harvested from 5 healthy donor horses between ages 11 and 17. These horses were euthanized due to non-musculoskeletal reasons.
• The aggregate cultures developed from these cells were treated with four different solutions: culture medium alone (control), 10 ng/mL IL-1β, 10 ng/mL IL-1β + 0.05 mg/mL MPA, or 10 ng/mL IL-1β + 0.5 mg/mL MPA for a duration of 24 hours.
• The extracellular matrix (ECM) gene expressions in the cell cultures were gauged using real-time polymerase chain reaction (rtPCR).
• The culture media matrix metalloproteinase (MMP) -3 and -13 concentrations were quantified via ELISA. Total glycosaminoglycan (GAG) content in the cell pellets and culture media was also assessed.

Study Findings

• It was observed that IL-1β and IL-1β combined with MPA significantly lowered ECM gene expression more in NBF cells compared to DDFT cells.
• In DDFT cells, IL-1β and IL-1β combined with MPA markedly upregulated MMP-3 culture media concentrations. An increase in MMP-13 culture media concentrations was more pronounced in NBF cells compared with DDFT cells when treated with the same chemicals.

Conclusions and Implications

• NBF cells were seen as more susceptible to the effects of IL-1β and MPA, particularly in terms of down-regulation of ECM gene expressions in vitro.
• This foundational data aids in further studies aiming to establish corticosteroid treatment regimens that could limit or alleviate inflammation while taking into account the biosynthesis of NBF cells. This is especially critical for treating horses with navicular disease, for which current data is inadequate.