Tissue reaction after intrastromal corneal ring implantation in an experimental animal model.
OBJECTIVE
To evaluate corneal wound healing in the hen animal model after additive surgery with an intracorneal ring segment (ICRS).


METHODS
We implanted one ICRS in each eye of 76 hens. In control group 1 (n = 22 hens), the stromal channel was prepared but no ICRS was inserted. In control group 2 (n = 2 hens), no surgery was performed. Animals were randomly separated into groups and euthanized after clinical follow-up of 4 and 12 hours, 1, 2, 3, and 7 days, and 1, 2, 3, 4, and 6 months. Corneas were stained with hematoxylin-eosin. Apoptosis was measured by terminal uridine nick end-labeling assays. Cell proliferation and myofibroblast-like differentiation were assayed by BrdU and α-smooth muscle actin immunofluorescence microscopy. Stromal matrix changes were documented by electron microscopy.


RESULTS
Epithelial and stromal cell apoptosis around the ICRS-implanted and control group 1 eyes peaked at 12 hours, but continued for 72 hours. In ICRS-implanted eyes, epithelial and stromal proliferation was present at 12 and 24 hours, respectively, and peaked at 7 days and 72 hours, respectively. Some proliferation in the ICRS-implanted group continued through the 6-month follow-up, and myofibroblast-like cells differentiated one to three months after ICRS implantation. The segments rotated within the stroma as the limbal inferior angle approached the epithelium.


CONCLUSIONS
Wound healing after ICRS implantation in hen corneas was similar to that of other corneal surgical wounds in stages. However, there were some specific features related to the small size of the epithelial wound and the device permanently implanted inside the cornea.
Group of Optical Diagnostic Techniques, Theorist, Atomic and Optical Physics Department, Faculty of Science, University of Valladolid, Valladolid, Spain, luciaibares@hotmail.com.
Lucía
L
Ibares-Frías
Patricia
P
Gallego
Roberto
R
Cantalapiedra-Rodríguez
María Cruz
MC
Valsero
Santiago
S
Mar
Jesús
J
Merayo-Lloves
María Carmen
MC
Martínez-García
D000818:Animals; D017209:Apoptosis; D049109:Cell Proliferation; D002645:Chickens; D060527:Corneal Keratocytes / Q000473:pathology; D003319:Corneal Stroma / Q000601:surgery* / Q000648:ultrastructure; D053938:DNA Fragmentation; D004195:Disease Models, Animal; D005549:Foreign-Body Reaction / Q000209:etiology* / Q000473:pathology; D020287:In Situ Nick-End Labeling; D058628:Myofibroblasts / Q000473:pathology; D019736:Prostheses and Implants; D019919:Prosthesis Implantation / Q000009:adverse effects*; D014945:Wound Healing / Q000502:physiology