Figure 4

Expression of extracellular matrix components in a healing tenascin C-null (knockout (KO)) cornea following an incision injury. (a) Protein expression of cellular fibronectin in a healing, incision-injured, cornea of a wild-type (WT) or a KO mouse as examined by immunohistochemistry. Cellular fibronectin is not detected in the corneal tissue of a WT (A, A′) and a KO (B, B′) mouse immediately after the incision injury. At day 5 post-incision injury, cellular fibronectin are detected in the stroma adjacent to the wound and in the newly formed granulation tissue in the incision injury in a WT stroma (C), but not seen in a KO stroma (D). The higher magnification picture of a WT cornea (C′) indicates the accumulation of cellular fibronectin in the stroma and minority of the basal epithelial cells. On the other hand, the KO cornea failed to form well-developed granulation tissue and the cells (arrowheads) adjacent to the wound are negative for cellular fibronectin at day 5 (D′). At day 10 post-incision injury, cellular fibronectin are detected mainly in the stroma adjacent to the wound in a WT stroma (E, E′), but not seen in a KO stroma (F). The higher magnification picture of a KO cornea (F′) show that the stroma in a KO cornea shows less cellularity at day 10 (F′). Frames A′–F′ show the higher magnification pictures of the quadrilateral area in each of Frames A–F. Nuclear staining, methylgreen; Epi, corneal epithelium; stroma, corneal stroma; glan, granulation tissue; scale bar, 100 μm (A–F) and 30 μm (A′–F′). (b). mRNA expression of collagen Iα1 chain in a healing incision-injured cornea. The loss of tenascin C significantly suppresses mRNA expression of collagen Iα1 at day 5. In a WT cornea, expression level of collagen Iα1 decreases at day 10 as compared with that at day 5. At day 10, there is no difference of the expression level of collagen I α1 between WT and KO corneas. **P<0.01.