Epimorphin expression during fetal eye development and corneal wound healing in mouse.

2002 Fiscal Year Final Research Report Summary

• Project/Area Number: 13671855
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Ophthalmology
• Research Institution: Nippon Medical school
• Principal Investigator: ISHIZAKI Masamichi Nippon Medical school, Medical, Assistant Prof., 医学部, 助教授 (40096954)
• Co-Investigator(Kenkyū-buntansha): TERASAKI Yasuhiro Univ. of Kumamoto, Medical, Assistant, 医学部, 助手 (50332870)
• Project Period (FY): 2001 – 2002
• Keywords: Epimorphin / eye development / Lens / Cornea

Research Abstract

The purpose of our study was to examine the expression of epimorphin in developing mouse eye and corneal wound healing by immunohistochemistry.
In the 10.5-day mouse embryo, the expression of epimorphin was observed in the invaginated lens vesicle circumference. In the 12-day embryo granular-shape positive reactions were recognized under the conjunctival epithelium. Furthermore, a slightly positive reaction for epimorphin was also observed under the developing corneal epithelium. In the 13-day embryo, during corneal development, positive reaction for epimorphin was observed in keratocyte. In this stage, the expression of epimorphin was confirmed in basement membrane under the corneal epithelium. In the 16-day embryo, the expression of epimorphin was recognized on the corneal extracellular matrix. Afterwards, positive intensity of epimorphin of corneal stroma increased gradually, and the strong positivity lasted from newborn to adult mouse. The distribution of epimorphin in adult mouse c ornea was observed in the basal layer of epithelial cell area by laser conforcal microscopy.
We further examined alteration of expressed epimorphin in the healing process of epithelium after scarping injury. In the second day of healing the injury, strong positive expression for epimorphin was detected in the corneal stroma surface denuded of epithelium. Coating of regenerating epithelium was noted rapidly afterwards.
These finding indicate that epimorphin participates in the eye development at embryonic stage. In addition, epimorphin was expressed in the stromal extracellular matrix, corresponding to the lamella structure formation stage of collagen fiber in cornea, which suggested its participation in the morphogenesis of corneal stroma. Furthermore, strong expression of epimorphin that has been recognized in adult cornea, suggest its participation in homeostasis of cornea as a constitutional composition of extracellular matrix, it was suggested that epimorphin of keratocyte origin participate in adhesion, differentiation and proliferation of regenerating epidermal cells.
We also performed molecular biological studies, but have not reached to concrete results at the present time. We are currently continuing this study to obtain additional results and intend to publish our findings in due course.