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Updated: Aug 31, 2026
Ex Vivo Corneal Organ Culture Model for Wound Healing Studies
Published on: February 15, 2019
Molecular mechanisms controlling the fibrotic repair phenotype in cornea: implications for surgical outcomes
Brian M Stramer1, James D Zieske, Jae-Chang Jung
1Bascom Palmer Eye Institute, University of Miami School of Medicine, Miami, Florida 33101, USA.
Purpose:
Incisional or ablation injury to the corneal stroma is repaired by deposition of a fibrotic tissue produced by activated keratocytes, whereas cells lost from the underlying stroma after epithelial abrasion are simply replaced by keratocyte replication without expression of fibrotic markers. The purpose of this study was to investigate mechanisms that determine this differential keratocyte response.
Methods:
A penetrating keratectomy rabbit model was adapted for mice to study the fibrotic repair response. A mouse epithelial abrasion model was applied to study the stromal cell replacement response. A primary rabbit corneal cell culture model and an organotypic culture model were also used.
Results:
When the epithelium was prevented from resurfacing the cornea after penetrating keratectomy, expression of fibrotic markers was considerably reduced. TGF-beta2 was determined to be a major substance produced by corneal epithelial cells capable of inducing the fibrotic phenotype. In the intact mouse cornea, TGF-beta2 was confined to the uninjured epithelium, but was released into the stroma during fibrotic repair. By contrast, TGF-beta1 was never found in the epithelium. When epithelial cells were cultured on a basement-membrane-like gel or allowed to deposit their own basement membrane in organotypic culture, TGF-beta2 production was reduced. Return of a basement membrane after wounding in vivo correlated with loss of the fibrotic phenotype. In the epithelial debridement injury model in which the basement membrane was left intact, TGF-beta2 remained confined to the corneal epithelium, consistent with the absence of a fibrotic phenotype.
Conclusions:
These data suggest that integrity of the basement membrane is a deciding factor in determining the regenerative character of corneal repair.
Insights
Corneal basement membrane integrity dictates repair outcomes. Intact basement membranes promote regeneration, while breaches trigger fibrotic responses via epithelial-derived TGF-beta2, influencing keratocyte behavior.
Area of Science:
- Ophthalmology
- Regenerative Medicine
- Cell Biology
Background:
- Corneal stromal injury can lead to either fibrotic repair by activated keratocytes or simple cell replacement without fibrosis.
- Understanding the mechanisms behind these differential keratocyte responses is crucial for developing effective corneal repair strategies.
Purpose of the Study:
- To investigate the molecular mechanisms that determine whether corneal keratocytes mount a fibrotic or regenerative repair response.
- To identify key factors influencing the differential behavior of corneal stromal cells following injury.
Main Methods:
- Utilized a mouse penetrating keratectomy model to study fibrotic repair and an epithelial abrasion model for stromal cell replacement.
- Employed primary rabbit corneal cell culture and organotypic culture models to further investigate cellular responses.
- Assessed the role of transforming growth factor-beta 2 (TGF-beta2) and basement membrane integrity in modulating keratocyte phenotype.
Main Results:
- Preventing epithelial resurfacing after penetrating keratectomy significantly reduced fibrotic marker expression.
- Epithelial-derived TGF-beta2 was identified as a key inducer of the fibrotic keratocyte phenotype.
- Basement membrane integrity was inversely correlated with TGF-beta2 production and fibrotic responses; its presence limited TGF-beta2 release and fibrosis.
Conclusions:
- The integrity of the corneal basement membrane is a critical determinant of the regenerative versus fibrotic nature of corneal wound healing.
- Maintaining basement membrane integrity may be a therapeutic target to promote corneal regeneration and prevent scarring.
