Fig. 4.

Implant–host integration at 6 wk after surgery. (A–C) Staining for procollagen type I. Positive staining is observed in matrix of both the implanted hydrogel (A) and the allograft control (B), indicating sites of new collagen deposition. (C) Unoperated control has no new collagen synthesis. (D–F) Staining for vimentin throughout stroma identifies stromal fibroblasts. Staining throughout the implanted hydrogel (D) demonstrates cell invasion. Cells may also been seen within the implanted allograft (E) and throughout the unoperated control (F). (G–I) Smooth muscle actin staining indicates activated myofibroblasts and the potential for scarring. In the hydrogel implant (G), staining is occasionally present in the hydrogel but is not found in the host stroma or the transition zone between host and implant. Positive staining in the allograft-implanted cornea (H) is identified in both the allograft and the transition zone but not the intact host stroma. (I) Unoperated control. e, epithelium; i, implant; g, allograft; s, stroma. (Bar = 100 μm in all cases.)