Collagen organization in the chicken cornea and structural alterations in the retinopathy, globe enlarged (rge) phenotype—An X-ray diffraction study

Boote, Craig; Hayes, Sally; Jones, Sadie; Quantock, Andrew J.; Hocking, Paul; Inglehearn, Chris F.; Ali, Manir; Meek, Keith Michael Andrew

doi:10.1016/j.jsb.2007.08.015

Cited by 30 publications

(34 citation statements)

References 30 publications

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“…However, in this study we chose the hen as the experimental animal since, histologically, its cornea resembles human cornea in size and structure: it is thinnest centrally and it thickens toward the periphery. Furthermore, the proportions of hen cornea layer [44,45] and the fibrillar collagen arrangement [46,47] are very similar to those of human cornea. Also, in previous experiments the hen was used as animal model to study the wound-healing response after intracorneal ring segment implantation by our group, so that the learning curve was already realized [48].…”

Section: Groups/ Treatmentmentioning

confidence: 57%

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

et al. 2010

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a b s t r a c tThe objective of this work was to evaluate the potential use of less stiff materials based on acrylic copolymers of methyl methacrylate/2-ethylhexyl acrylate (MMA/EHA) as devices to correct, stabilize and improve the effect of poly(methyl methacrylate) (PMMA) intracorneal ring segments. MMA/EHA and PMMA intracorneal ring segments were surgically implanted in the corneas of Lohmann Classic hens. The effects of the intracorneal ring segments were assessed by optical measurements and corneal tolerance was evaluated through biomicroscopic examination over a 90-day observation period and by conventional histology. The experimental results demonstrated that the intracorneal ring segments made of MMA/EHA copolymers provided a significant change in the corneal curvature and an improved in vivo response compared to those obtained for PMMA rings, which was attributed to the higher flexibility of the copolymeric materials, indicating that these systems might be considered suitable as an alternative to those currently used, for application in clinical practice.

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Section: Groups/ Treatmentmentioning

confidence: 57%

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

et al. 2010

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“…First, the corneal measurements were not exactly the same as those in humans; so, for this reason, we had to create and adapt the surgical instruments to our animal model. Second, there are differences in the collagen arrangement [42] and accommodation mechanism [43,44], although we believe that these did not interfere with the wound healing process. Future studies will be performed to examine the tissue reactions measured as changes in mRNA and protein expression to better understand this specific wound healing response.…”

Section: Discussionmentioning

confidence: 93%

Tissue reaction after intrastromal corneal ring implantation in an experimental animal model

Ibares‐Frías

Gallego

Cantalapiedra-Rodríguez

et al. 2015

Graefes Arch Clin Exp Ophthalmol

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Purpose 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 ICRSimplanted 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.

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“…For this reason we had to create and adapt the surgical instruments for our animal model. Secondly, there are differences in the collagen arrangement [32] and accommodative mechanism, [24,25] although we believe that these would not interfere with the clinical and wound healing process.…”

Section: Discussionmentioning

confidence: 96%

Validation of an Experimental Animal Model for Corneal Additive Surgery

Gallego¹

2014

J Clin Exp Ophthalmol

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Purpose: To assess the hen cornea as a model for training and future wound healing studies after implantation of intrastromal corneal ring segments (ICRS) by clinical and optical outcomes.Setting: University of Valladolid, Valladolid, Spain.Design: Experimental study. Methods:One 90°, 150-µm thick polymethyl methacrylate Ferrara ICRS segment was manually implanted at 70-80% depth of 192 Gallus domesticus corneas. Clinical follow-up for 6 months included monitoring corneal thickness, epithelial wound closure, edema, haze, and the location and severity of deposits. The refractive state was also measured. After each animal was euthanized, corneas were processed for direct transmittance and histological analysis. Results:Complications were present in 16% of the eyes. Epithelial wound closure was completed at 3 ± 2 days. A slight corneal edema in the channel site was present for the first 15 days. All corneas had deposits by 4 months located along the inner, outer curvatures and under the segments. Corneal haze was present only at the incision site. ICRS induced hyperopic changes in the refractive state without changes in direct transmitance of central cornea. New cells and extracellular matrix were present around the segment where deposits were seen on clinical follow-up. Conclusions:With hen as an animal model, ICRS were implanted in a precise and reproducible way after a learning curve. Similar to humans, the follow-up period during the first 6 months after implantation showed fast wound closure, deposits, and haze at the incision site. ICRS in hens also reduced the refractive power without affecting the central cornea.

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Collagen organization in the chicken cornea and structural alterations in the retinopathy, globe enlarged (rge) phenotype—An X-ray diffraction study

Cited by 30 publications

References 30 publications

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

Clinical and pathological effects of different acrylic intracorneal ring segments in corneal additive surgery

Tissue reaction after intrastromal corneal ring implantation in an experimental animal model

Validation of an Experimental Animal Model for Corneal Additive Surgery

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