Abstract
Purpose: :
To evaluate biosynthesized acellular membranes for reconstruction of cornea in deep stromal damage using vitrified type-I collagen (called collagen Vitrigel, CV) with enhanced optical transparency, and handling convenience of processing and storage, compared to amniotic membrane, the current standard of ocular care.
Methods: :
The CV membrane was made from collagen type-I solution, and prepared through a three-stage sequence: gelation, vitrification, and rehydration. The transparency of CV membrane was examined using Perkin-Elmer spectrophotometer. Fibrin glue (FG) was applied to affix the CV membrane to injured corneas. In vivo applications were conducted on 21 New Zealand White rabbits. Lamellar keratectomy was performed on the cornea of the rabbits to remove the anterior corneal layers with diameter of 8 mm and thickness of about 100 µm. The corneal reconstruction using FG-assisted CV membrane was compared with injure-only, FG-alone, and sutured CV controls over ten weeks. Various examinations were performed, including ophthalmoscope examination, fluorescein (0.25%) staining for epithelial defect, hematoxylin and Eosin staining, immunostaining for cytokeratins K3/K12 as a marker of reconstructed and control corneas and collagen type I, and transmission electron microscopy.
Results: :
The hydrated CV membrane with thickness of 50 µm exhibited a transmittance from 66-90% at visible light wavelengths from 400-800 nm. The injured corneas treated using FG-assisted CV membrane demonstrated optical transparency and stable host-graft integration through 10 weeks. Yet, the corneas sutured with CV membrane caused scarring and neovascularization. An FG-only control exhibited an invasion of epithelial cells into the surrounding stroma at 2 weeks. In contrast, FG-assisted CV membrane successfully integrated into the recipient stroma layer. In the injury-only control, the reconstructed epithelium was unstable, initially covering the whole cornea at 12 days, but exhibiting a reappearance of a central defect at 21 days.
Conclusions: :
We demonstrated that the transparent CV membrane assisted with FG was suitable for the corneal reconstruction of deep stromal damage and showed excellent integration with the recipient cornea. This biosynthesized acelluar membrane not only features superiority as standardized materials for corneal reconstruction, but also holds great potential for further modifications in its physical, biological, and drug delivery properties.
Keywords: cornea: basic science