Abstract
Purpose :
A corneal epithelium-specific Sonic hedgehog (Shh) knockout mouse line is produced to examine the roles of endogenous Shh in epithelial wound healing. Its function in maintaining tissue homeostasis in adults remains elusive, although exogenous Shh enhances corneal epithelium repair (Saika S et al. IOVS, 2004).
Methods :
Mice carrying Krt12-Cre (Hayashi Y et al. IOVS, 2010) and those carrying Shhf/f (Dassule H.R. et al. Development, 2000) were mated to generate a bi-transgenic Krt12Cre/wt/Shhf/f (ShhΔCE) mouse line. An epithelial debridement (2 mm in diameter) was produced at the center of demarcated cornea of right eye of 8-week-old male ShhΔCE and Shhf/wt (Krt12wt/wt/Shhf/wt) mice with a micro-surgical blade. Epithelial wound healing and cell proliferation were assessed at 6, 12, 18, 24 and 36 hrs post-injury by Image J software and BrdU immunostaining, respectively.
Results :
Corneal epithelial debridement caused an up-regulation of cell proliferation in both ShhΔCE and Shhf/wt mice in comparison to naïve/uninjured corneas. The increment of BrdU-positive cells was counteracted in ShhΔCE mice compared with Shhf/wt in healing epithelium at 18 hrs after injury. The size of the remaining epithelial defect was not significantly altered in ShhΔCE as compared with Shhf/wt mice.
Conclusions :
Endogenous Shh is required for up-regulation of cell proliferation in healing corneal epithelium in the later phase. Further experiment is required to elucidate the effects of complete loss of Shh on the corneal epithelial wound healing using homozygous Krt12Cre/Cre/Shhf/f mice.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.