Surface topography as a tool to detect early changes in a posttraumatic equine model of osteoarthritis.

The equine model of posttraumatic osteoarthritis (OA) mimics certain aspects of the naturally occurring disease, both in horses and humans. The objective of this study was to assess articular cartilage degeneration in a posttraumatic OA model using the established macroscopic and microscopic scoring systems and compare them with a novel surface topography analysis. OA was induced in the carpal joint of 15 (n = 15) mixed breed horses. Surface changes on the articular cartilage were characterized using osteochondral blocks from the third carpal bone (C3) and radial carpal bone using surface topography, standard histological grading, and gross evaluation of the joints. Significant differences were observed between OA and non-OA joints for gross evaluation scores. Microscopic scores of hematoxylin and eosin and Safranin O and Fast Green-stained sections demonstrated no differences between OA and non-OA joints. However, articular cartilage from the induced OA joint had significantly greater surface topography measurements compared with the sham treatment group, consistent with the changes seen on gross evaluation of joints. No significant correlations were noted between surface roughness measurements, histological assessment, and gross evaluation scores. The results suggest that surface topography analysis may provide a reliable objective approach to assess early changes in the cartilage surface in OA.

Expansion of mesenchymal stem cells on fibrinogen-rich protein surfaces derived from blood plasma.

Mesenchymal stem cells (MSCs) are present in low density in bone marrow and culture expansion is necessary to obtain sufficient numbers for many proposed therapies. Researchers have characterized MSC growth on tissue culture plastic (TCP), although few studies have explored proliferation on other growth substrates. Using adult equine MSCs, we evaluated proliferation on fibrinogen-rich precipitate (FRP) surfaces created from blood plasma. When seeded at 1 × 10(4) cells/cm(2) and passaged five times over 10 days, MSCs on FRP in medium containing fibroblast growth factor 2 (FGF2) resulted in a ∼2.5-fold increase in cell yield relative to TCP. In FGF2-free medium, FRP stimulated a 10.4-fold increase in cell yield over TCP after 10 days, although control cultures maintained in FGF2 on TCP demonstrated that the stimulatory effect of FRP was not as lasting as that of FGF2. Chondrogenic cultures demonstrated that FRP did not affect differentiation. On TCP, MSCs seeded at 500 cells/cm(2) experienced a 4.6-fold increase in cell yield over cultures seeded at 1 × 10(4) cells/cm(2) following 10 days of expansion. In 500 cells/cm(2) cultures, FRP stimulating a two-fold increase in cell yield over TCP without affecting differentiation. Low-density FRP cultures showed a more even distribution of cells than TCP, suggesting that FRP may accelerate proliferation by reducing contact inhibition that slows proliferation. In addition, FRP appears capable of binding FGF2, as FRP surfaces pre-conditioned with FGF2 supported greater proliferation than FGF2-free cultures. Taken together, these factors indicate that substrates obtained from simple and inexpensive processing of blood enhance MSC proliferation and promote efficient coverage of expansion surfaces.