title: Evaluation of the AlgerBrush II rotating burr as a tool for inducing ocular surface failure in the New Zealand White rabbit.
abstract: The New Zealand White rabbit has been widely used as a model of limbal stem cell deficiency (LSCD). Current techniques for experimental induction of LSCD utilize caustic chemicals, or organic solvents applied in conjunction with a surgical limbectomy. While generally successful in depleting epithelial progenitors, the depth and severity of injury is difficult to control using chemical-based methods. Moreover, the anterior chamber can be easily perforated while surgically excising the corneal limbus. In the interest of creating a safer and more defined LSCD model, we have therefore evaluated a mechanical debridement technique based upon use of the AlgerBrush II rotating burr. An initial comparison of debridement techniques was conducted in situ using 24 eyes in freshly acquired New Zealand White rabbit cadavers. Techniques for comparison (4 eyes each) included: (1) non-wounded control, (2) surgical limbectomy followed by treatment with 100% (v/v) n-heptanol to remove the corneal epithelium (1-2 min), (3) treatment of both limbus and cornea with n-heptanol alone, (4) treatment of both limbus and cornea with 20% (v/v) ethanol (2-3 min), (5) a 2.5-mm rounded burr applied to both the limbus and cornea, and (6) a 1-mm pointed burr applied to the limbus, followed by the 2.5-mm rounded burr applied to the cornea. All corneas were excised and processed for histology immediately following debridement. A panel of four assessors subsequently scored the degree of epithelial debridement within the cornea and limbus using masked slides. The 2.5-mm burr most consistently removed the corneal and limbal epithelia. Islands of limbal epithelial cells were occasionally retained following surgical limbectomy/heptanol treatment, or use of the 1-mm burr. Limbal epithelial cells were consistently retained following treatment with either ethanol or n-heptanol alone, with ethanol being the least effective treatment overall. The 2.5-mm burr method was subsequently evaluated in the right eye of 3 live rabbits by weekly clinical assessments (photography and slit lamp examination) for up to 5 weeks, followed by histological analyses (hematoxylin & eosin stain, periodic acid-Schiff stain and immunohistochemistry for keratin 3 and 13). All 3 eyes that had been completely debrided using the 2.5-mm burr displayed symptoms of ocular surface failure as defined by retention of a prominent epithelial defect (∼40% of corneal surface at 5 weeks), corneal neovascularization (2-3 quadrants), reduced corneal transparency and conjunctivalization of the corneal surface (demonstrated by the presence of goblet cells and/or staining for keratin 13). In conclusion, our findings indicate that the AlgerBrush II rotating burr is an effective method for the establishment of ocular surface failure in New Zealand White rabbits. In particular, we recommend use of the 2.5-mm rotating burr for improved efficiency of epithelial debridement and safety compared to surgical limbectomy.
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia. Electronic address: Fiona.li@qei.org.au.
authors.forename: Fiona J
authors.initials: FJ
authors.lastname: Li
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia; School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, 2 George Street, Brisbane, Australia; Institute of Health & Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Queensland, 4059, Australia. Electronic address: elham.niliahmadabadi@hdr.qut.edu.au.
authors.forename: Elham
authors.initials: E
authors.lastname: Nili
authors.affiliation: UQ Biological Resources, The University of Queensland, Herston, Queensland, Australia. Electronic address: c.lau1@uq.edu.au.
authors.forename: Cora
authors.initials: C
authors.lastname: Lau
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia; School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, 2 George Street, Brisbane, Australia; Institute of Health & Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Queensland, 4059, Australia. Electronic address: n.richardson@qut.edu.au.
authors.forename: Neil A
authors.initials: NA
authors.lastname: Richardson
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia. Electronic address: jennifer.young@qei.org.au.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Walshe
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia; School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, 2 George Street, Brisbane, Australia. Electronic address: nigel.barnett@qei.org.au.
authors.forename: Nigel L
authors.initials: NL
authors.lastname: Barnett
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia. Electronic address: brendan.cronin@qei.org.au.
authors.forename: Brendan G
authors.initials: BG
authors.lastname: Cronin
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia; The Australian Pterygium Centre, 232 Oxley Road, Graceville, Queensland, 4075, Australia. Electronic address: lawrie@tapc.net.au.
authors.forename: Lawrence W
authors.initials: LW
authors.lastname: Hirst
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia; Department of Ophthalmology, University of California Davis, 4860 Y Street, Suite 2400, Sacramento, CA 95817, USA. Electronic address: irschwab@ucdavis.edu.
authors.forename: Ivan R
authors.initials: IR
authors.lastname: Schwab
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia; Science & Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, 4001, Australia; Faculty of Medicine & Biomedical Sciences, University of Queensland, Herston, Queensland, 4029, Australia; Australian Institute for Bioengineering and Nanotechnology, University of Queensland, St Lucia, Queensland, 4072, Australia; Faculty of Science, University of Western Australia, Crawley, Western Australia, 6009, Australia. Electronic address: traian.chirila@qei.org.au.
authors.forename: Traian V
authors.initials: TV
authors.lastname: Chirila
authors.affiliation: Queensland Eye Institute, 140 Melbourne Street, South Brisbane, Queensland, 4101, Australia; School of Biomedical Sciences, Faculty of Health, Queensland University of Technology, 2 George Street, Brisbane, Australia; Institute of Health & Biomedical Innovation, Queensland University of Technology, 60 Musk Avenue, Kelvin Grove, Queensland, 4059, Australia. Electronic address: d.harkin@qut.edu.au.
authors.forename: Damien G
authors.initials: DG
authors.lastname: Harkin
mesh_terms: D000818:Animals; D003315:Cornea / Q000473:pathology / Q000601:surgery*; D003646:Debridement / Q000295:instrumentation* / Q000379:methods; D004195:Disease Models, Animal; D019573:Epithelium, Corneal / Q000601:surgery*; D005260:Female; D016850:Limbus Corneae / Q000473:pathology / Q000601:surgery; D011817:Rabbits; D013234:Stem Cells / Q000166:cytology; D013523:Surgical Equipment
keywords: Animal models; Cornea; Debridement; Limbal stem cell deficiency; New Zealand White rabbit; Ocular surface failure; Rotating burr; Wound healing