The Effect of Synovial Fluid Enzymes on the Biodegradability of Collagen and Fibrin Clots

Abstract

Recently there has been a great deal of interest in the use of biomaterials to stimulate wound healing. This is largely due to their ability to centralize high concentrations of compounds known to promote wound healing at a needed location. Joints present a unique challenge to using scaffolds because of the presence of enzymes in synovial fluid which are known to degrade materials that would be stable in other parts of the body. The hypothesis of this study was that atelocollagen scaffolds would have greater resistance to enzymatic degradation than scaffolds made of gelatin, fibrin and whole blood. To test this hypothesis, collagen and fibrin-based scaffolds were placed in matrix metallopeptidase-1 (MMP-1), elastase, and plasmin solutions at physiologic concentrations, and the degradation of each scaffold was measured at varying time points. The atelocollagen scaffolds had a significantly greater resistance to degradation by MMP-1, elastase and plasmin over the fibrin based scaffolds. The results suggest that atelocollagen-based scaffolds may provide some protection against premature degradation by synovial fluid enzymes over fibrin-based matrices.

Figure 1

Enzymatic degradation of atelocollagen, gelatin, fibrin, and blood clot scaffolds over a 48 h period by (A) MMP-1; (B) Elastase and (C) Phosphate buffered saline (PBS) (control). By 24 h in the MMP-1 solution, the only remaining scaffolds with any integrity were the atelocollagen scaffolds and by 48 h, even the atelocollagen scaffolds had been degraded. † denotes significantly less degradation of the atelocollagen scaffolds at 12, and 24 h (p < 0.02). * denotes significantly less degradation of the blood clot scaffold than the fibrin or gelatin at the time points identified (p < 0.001 for all comparisons).

Figure 1

Enzymatic degradation of atelocollagen, gelatin, fibrin, and blood clot scaffolds over a 48 h period by (A) MMP-1; (B) Elastase and (C) Phosphate buffered saline (PBS) (control). By 24 h in the MMP-1 solution, the only remaining scaffolds with any integrity were the atelocollagen scaffolds and by 48 h, even the atelocollagen scaffolds had been degraded. † denotes significantly less degradation of the atelocollagen scaffolds at 12, and 24 h (p < 0.02). * denotes significantly less degradation of the blood clot scaffold than the fibrin or gelatin at the time points identified (p < 0.001 for all comparisons).

Figure 2

Enzymatic degradation of atelocollagen, gelatin, fibrin, and blood clot scaffolds over a 48 h period by (A) plasmin and (B) water (control). † denotes significantly less degradation by plasmin of atelocollagen and gelatin scaffolds than the blood clot or fibrin clot (p < 0.05 for all comparisons).

Figure 3

Cell proliferation within atelocollagen and gelatin scaffolds at 2 and 10 days after seeding as measured by the MTT assay. Cell numbers in both types of scaffolds increased between 2 and 10 days. Atelocollagen scaffolds had a higher cell concentration at 2 days. † denotes significantly higher cell number in the atelocollagen scaffolds at 2 days (p < 0.05).

Figure 4

Contraction of scaffolds cultured for 9 days measured as a percentage of initial area. The atelocollagen scaffolds had a greater reduction in surface area than the gelatin scaffolds. A similar trend was seen for cell seeded scaffolds, and non-cell seeded scaffolds. * denotes significantly greater contraction of the cell seeded atelocollagen scaffold compared to the cell seeded gelatin scaffold (p < 0.05).