FIG. 5.

Histological image analysis. Human smooth muscle cells were seeded on the ablumenal surface and cultured under specified perfusion conditions for 21 days. (A) Hematoxylin and eosin stained sections show cell migration across the scaffold as a function of each respective gas condition. These data show constructs cultured using controlled O₂ gradients to have increased cell migration relative to all other conditions. (B) Masson's Trichrome staining was used to assess collagen and ECM fiber alignment within the remodeled zone. Constructs cultured under 11% O₂ conditions displayed dense regions of amorphous collagen fibers (blue) at the leading edge of the migration front with reduced fiber deposition between densely packed cells (red). Under these hypoxic conditions, cells were predominantly localized within 50–100 μm of the seeded surface. (C) Under 11%:21% O₂ gradient conditions, cells migrated across the bulk scaffold and appear more disperse relative to other conditions. No specific fiber alignment or structure was noted. (D) Results from the 21% O₂ samples were similar to the 11% O₂ conditions, displaying a leading edge of cell migration that reached the ∼250–300 μm from the seeded surface, with dense regions of amorphous collagen fibers (blue) at the lead edge. The distance of cell migration from the ablumenal surface is shown by an arrow, “→”, pointing from the ablumenal surface, indicated by “■”, to the leading edge of cell migration, indicated by a “- - -” line, with the lumenal side indicated by “●”. Color images available online at www.liebertpub.com/tea