Figure 7. Smad3 directly associated with stromal ECM protein modulation impacted the corneal stromal wound healing in mice after alkali injury during active wound healing. A: H&E staining showing the morphological architecture of Smad3^+/+ naïve (a); Smad3^−/− naïve (b); Smad3^+/+ post-alkali injury (c); and Smad3^−/−- post-alkali injury (d) corneal tissue sections at day 21. No structural changes were observed in Smad3^−/− and Smad3^+/+ naïve corneal tissue sections. An increased cellular infiltration and distorted collagen lamellae (arrows) were observed in the corneal stroma of Smad3^+/+ and Smad3^−/− compared with Smad3^−/− mouse corneal tissue sections after alkali injury at day 21. B: Masson’s trichrome staining showed the gross collagen level in Smad3^+/+ naïve (a); Smad3^−/− naïve (b); Smad3^+/+ post-alkali injury (c); and Smad3^−/− post-alkali injury (d) corneal tissue sections at day 21. No collagen levels were altered in Smad3^−/− and Smad3^+/+ naïve corneal tissue sections. Increased collagen deposition was observed in the corneal stroma of Smad3^+/+ compared with Smad3^−/− mouse corneal tissue sections after alkali injury at day 21, as indicated by increased blue color intensity (arrowhead). Scale bar = 200 μm.