MT3-MMP (MMP-16) is downregulated by in vitro cytokine stimulation of cartilage, but unaltered in naturally occurring equine osteoarthritis and osteochondrosis.

The article investigates the role of MT3-MMP, a type of metalloproteinase thought to contribute to joint disease, in horses with osteoarthritis and osteochondrosis, determining that it doesn’t appear to be altered in these conditions. However, these enzymes were found to be downregulated by cytokines, implying they may not be largely involved in the degradation of cartilage in equine disease.

Introduction

• The study focuses on MT3-MMP (Membrane-type matrix metalloproteinase-3), a metalloproteinase involved in matrix degradation, a critical process observed in many joint diseases.
• Previous research revealed increased MT3-MMP expression in human cartilage suffering from end-stage osteoarthritis, implying a possible role for this protein in the disease’s progression.

Study Objective

• The primary goal of the research was to explore whether MT3-MMP is regulated in cartilage similarly in two common arthropathies – osteoarthritis and osteochondrosis – in horses.
• Another focus was to investigate how proinflammatory cytokines could potentially influence MT3-MMP expression.

Methodology and Findings

• MT3-MMP expression was analyzed in cartilage samples from horses diagnosed with osteoarthritis and osteochondrosis.
• These results were then compared with MT3-MMP levels in normal, age-and site-matched horse cartilage.
• In addition, normal cartilage was subjected to stimulation with proinflammatory cytokines, and then assessed for MT3-MMP quantity.
• Results showed that MT3-MMP expression was not significantly altered in cartilage from osteoarthritis or osteochondrosis affected horses.
• However, in vitro studies indicated that proinflammatory cytokines, such as human interleukin-1beta, oncostatin M, or tumor necrosis factor-alpha, could significantly downregulate MT3-MMP gene expression.

Conclusion

• The findings of this study suggest that MT3-MMP may not have a major role in the matrix destruction witnessed in equine cartilage diseases.
• The researchers propose further investigation to better understand the regulation and function of MT3-MMP, given these results and established knowledge of its elevated presence in human end-stage osteoarthritis.