Expression and distribution of tissue transglutaminase in normal and injured rat cornea.

To determine the expression and distribution of tissue transglutaminase (TG[subc]) and extracellular matrix (ECM) proteins in rat cornea during epithelial wound healing. Methods. Corneal epithelial defects were created in rat corneas, and TG[subc] expression was examined by Northern blot analysis, in situ hybridization, and immunohistochemical staining after the injury. The presence of fibrinogen, laminin-l, nidogen/entactin, and type collagen was also determined immunohistochemically. Results. TG[subc], was expressed in normal corneas. During the early wound healing process, TG[subc] mRNA expression was up-regulated and TG[subc] immunoreactivity was predominantly expressed in the migrating epithelial cells. ECM proteins were also expressed in a similar pattern as TG[subc]. Conclusions. The sites and lime course of TG[subc] expression indicate that TG[subc] probably plays a role in maintaining the homeostasis of the cornea and in promoting epithelial wound healing. The simultaneous expression of TG[subc] and ECM proteins suggests that the ECM proteins probably operate in concert with TG[subc] in corneal wound healing. [ABSTRACT FROM AUTHOR]