Keratocyte Repopulation in UVB-Exposed Thioltransferase Knockout Mice

Purpose: Thioltransferase is involved in cell protein homeostasis and DNA synthesis. It inhibits apoptosis and stimulates cell proliferation. Keratocyte repopulation after ultraviolet B (UVB) damage was studied in corneas of thioltransferase (-/-) mice. Methods: Six wild type mice and six thioltransferase (-/-) mice corneas were exposed at 300 nm UV-radiation at a dose producing damage in the corneal stroma (8 kJ/m2). Animals were killed 3 and 7 days after exposure. Corneas were processed for light microscopy. Results: All corneas of wild type mice and thioltransferase (-/-) mice showed extensive damage 3 days after UVB exposure. Keratocytes disappeared throughout the entire thickness of the UVB-damaged central stroma. Corneal thickness was nearly doubled compared with non-treated control corneas. However, 7 days after UVB exposure corneas of wild type mice were almost completely repopulated by keratocytes, only superficial ¼ of the stroma was still free of keratocytes. Corneal thickness was almost normal. Corneal stroma in the thioltransferase (-/-) mice 7 days after UV exposure was still not repopulated by keratocytes and the corneas were still very thick. Conclusions: The keratocyte repopulation in thioltransferase (-/-) mice is delayed. Thioltransferase seems to play an important role in the corneal wound healing and keratocyte repopulation after UVB induced damage.