Objective: To compare the effects of triamcinolone acetonide (TA) and methylprednisolone acetate (MPA) on expression of selected chondrocyte genes in recombinant equine interleukin-1β (reIL-1β) stimulated articular cartilage explants.
Design: In vitro experiment.
Animals: Horses (n = 6).
Procedures: Articular cartilage explants from 2- to 3- year-old horses were exposed to reIL-1β in the presence and absence of TA and MPA at 10(-7) and 10(-6) M. Resting levels of mRNA of anabolic and catabolic genes of chondrocyte origin were quantified using qPCR after 6- and 12-hour incubations. Genes of interest included aggrecan interglobular domain, aggrecan, and collagen II, matrix metalloproteinases 3 and 13 (MMP3, MMP 13), aggrecanase 1, tissue inhibitor of matrix metalloproteinases 1 and 2 (TIMP 1, TIMP 2), BCL 2, vascular endothelial growth factor, and cyclooxygenase 2 (COX 2).
Results: IL-1β significantly influenced the expression of most transcripts. MPA and TA inhibited the induction of MMP 13 at 6 and 12 hours; an effect that was significant at 6 hours with MPA at 10(-7) M and TA at 10(-6) M. Similarly, COX 2 was induced by reIL-1β and MPA and TA significantly inhibited its upregulation. TIMP 2 expression was reduced by reIL-1β, an effect that was significantly abrogated by MPA and TA. There were no significant differences observed between glucocorticoids for any gene studied.
Conclusions: No differential effects of MPA or TA on chondrocytic gene expression were identified suggesting that any divergent influences of these glucocorticoids on chondrocyte metabolism are posttranslational.
© Copyright 2012 by The American College of Veterinary Surgeons.