Assessment of cartilage degradation effects of matrix metalloproteinase-13 in equine cartilage cocultured with synoviocytes.

The research article explores the effects of a protein known as matrix metalloproteinase-13 (MMP-13) on the expression of cartilage matrix molecule genes in horse cartilage and synoviocytes. It compares this to the effect of interleukin (IL)-1alpha, another protein.

Study Design

• The study was performed using articular cartilage and synovium tissues obtained from the femoropatellar joints (knee joint) of 4 young horses between 3 to 5 years old.
• Synoviocytes, cells that line the joints, were isolated and as well as cartilage explants (tissue samples).
• These cells and tissue samples were then cocultured, or grown together, in a laboratory environment. This was done to create a model which mimics the interaction between these cells and tissues in the body.
• The cocultured samples were treated with different concentrations of human recombinant MMP-13 or IL-1alpha proteins, and observed for 96 hours. These proteins were added in varying concentrations to examine their effects on cartilage and synoviocyte cells.

Data Collection and Analysis

• Cartilage and media were taken from the cultures and examined for their content of glycosaminoglycan (GAG), a molecule that plays a crucial role in forming cartilage. The results were adjusted according to the DNA content of the cartilage.
• Quantitative Polymerase Chain Reaction (qPCR), a technique for amplifying and measuring specific DNA sequences, was performed on mRNA from the cartilage and synoviocytes to assess the expression of four genes: MMP-3, MMP-13, aggrecan, and COL2A1.
• The data was adjusted according to the expression of 18S ribosomal subunit mRNA, which served as a control.

Results and Conclusions

• The concentration of GAG in the culture media increased in those cultures treated with either MMP-13 or IL-1alpha over the study duration.
• The expression of aggrecan and COL2A1 genes, vital for the health and function of cartilage, was noted to increase in response to the application of either of the two proteins.
• Interestingly, the expression of MMP-3, which plays a role in cartilage degradation, also increased in both the cartilage and synoviocytes treated with either MMP-13 or IL-1alpha.
• The expression of MMP-13, however, showed a differing response. Its mRNA expression in cartilage instances was increased by IL-alpha but decreased in synoviocytes by MMP-13 treatment.
• Taken together, these findings support the use of MMP-13 in coculture system that includes synoviocytes and cartilage explants for studying osteoarthritis, a degenerative joint disease.