A morphological study of the rabbit corneal assay
Abstract:
We present a morphological study of the rabbit corneal assay. The effects of corneal pockets filled with methylcellulosis carriers with and without basic fibroblast growth factor (bFGF) were studied 4, 7, 11, 14 and 21 days following surgery. In the controls, strongly vacuolated keratocytes are present at the borders and especially at the bottom of the pocket. A large number of such cells can also be found in the region between the pocket and the epithelium. These cells obviously undergo necrosis. A few vacuolated keratocytes with poorly structured cytoplasm can even be found in the stroma between the pocket and the limbus. There are also changes in the epithelium. It is thinner than normal and the cells are longitudinally oriented. Construction of the pocket sometimes results in a fissure extending a variable distance from the bottom of the pocket to the limbus. Basic FGF induced blood-vessel growth from the limbus into the cornea. At least until day 7 this is accompanied by high vulnerability of the vessels, and changes in the pattern and structure of the extracellular matrix. Neutrophilic granulocytes, monocytes and a few mast cells migrate in front of the vessels. As in the controls, vacuolated and necrotic keratocytes are present within the stroma. From day 11 onward, many more vessels can be found in front of than behind the pocket, often located adjacent to vacuolated keratocytes. We suggest that an angiogenic substance placed in the corneal pocket is not the only angiogenic stimulus in the test, but acts together with many stimuli caused by the surgical manipulations.
Insights
This study examines rabbit corneas after surgery. Basic fibroblast growth factor (bFGF) promotes blood vessel growth, but surgical factors also stimulate this angiogenesis.
Area of Science:
- Ophthalmology
- Regenerative Medicine
- Tissue Engineering
Background:
- Corneal wound healing involves complex cellular and matrix changes.
- Basic fibroblast growth factor (bFGF) is a known angiogenic factor.
- Surgical interventions can induce inflammatory and regenerative responses in the cornea.
Purpose of the Study:
- To investigate the morphological effects of corneal pockets containing methylcellulosis carriers with and without bFGF.
- To analyze the cellular and extracellular matrix responses in the rabbit cornea post-surgery.
- To elucidate the role of bFGF in corneal angiogenesis and healing.
Main Methods:
- Morphological study of rabbit corneal assays.
- Creation of corneal pockets filled with methylcellulosis carriers +/- bFGF.
- Histological analysis at 4, 7, 11, 14, and 21 days post-surgery.
Main Results:
- Control corneas showed keratocyte vacuolation and necrosis, epithelial thinning, and fissures.
- bFGF induced significant blood vessel growth (angiogenesis) from the limbus into the cornea.
- Inflammatory cells (neutrophils, monocytes, mast cells) infiltrated the cornea, particularly near new vessels.
- Extracellular matrix changes and vessel vulnerability were observed early after bFGF application.
- Post-surgical stimuli, in addition to bFGF, likely contribute to angiogenesis.
Conclusions:
- bFGF promotes corneal angiogenesis, but its effect is modulated by surgical trauma.
- The rabbit corneal assay provides a model to study wound healing and angiogenesis.
- Corneal surgery induces cellular necrosis and inflammatory responses that may interact with applied growth factors.
