Anisotropic and refractive properties of the cornea of rabbits following implantation of type I collagen inlays extracted from bovine digital flexor tendon

• Grant number: 16/00743-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: October 01, 2016
• End date: December 09, 2018
• Field of knowledge: Agronomical Sciences - Veterinary Medicine - Animal Clinics and Surgery
• Principal Investigator: José Luiz Laus
• Grantee: Alexandre Augusto Franchi de Barros Sobrinho
• Host Institution: Faculdade de Ciências Agrárias e Veterinárias (FCAV). Universidade Estadual Paulista (UNESP). Campus de Jaboticabal. Jaboticabal , SP, Brazil

Abstract

Polymers, in ophthalmology, have been used for building biomaterials (membranes, hydrogels, micelles, liposomes and other devices), for drugs or cells delivery systems, or for corneal inlays and onlays. There is an interest in expanding the range of polymeric materials capable of integrating the cornea without risk of rejection, and to promote rearrangements in the supramolecular organization of the stromal extracellular matrix (ECM). There is evidence that such rearrangements can change refractive properties. In this study, collagen-based biomaterials will be studied as a raw material for making corneal inlays. They are prepared with collagen type I bovine digital flexor tendon, which is extracted in glacial acetic acid 0.5 M for 72 hours. The acid-soluble fraction of collagen is reconstituted with 10M sodium hydroxide solution subsequently dialyzed for obtaining gels, and dried in an oven for the preparation of pure collagen membrane. The membranes will be, first, studied in vitro as the supraorganization parameters and crystallinity of the collagen fibers and swelling related to physical and chemical stability. Subsequently, in vivo studies will be conduct where collagen membranes will be tested as corneal inlays. The right eyes of adults, males or females, healthy New Zealand White rabbits will be used eyes breed rabbits rights New Zealand White. A pocket is created in the cornea for deployment and positioning of the membranes (inlays) in the stroma of collagen cornea. Eyes will be evaluated for the refractive properties every seven days for 35 days. After the animals are euthanized and the corneas will be collected for studies on optical anisotropy (birefringence and linear dichroism). All continuous variables are tested for statistical normality. Variables with Gaussian distribution will be compared with ANOVA; parameters with non-Gaussian distribution will be compared with the Kruskal-Wallis test. Differences will be considered significant when the p value is less than 5% with 95% confidence intervals (± 2 EP).

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

SOBRINHO, Alexandre Augusto Franchi de Barros. Anisotropic and refractive properties of rabbit corneas, after implantation of type I collagen inlays extracted from bovine superficial digital flexor tendon. 2019. Doctoral Thesis - Universidade Estadual Paulista (Unesp). Faculdade de Ciências Agrárias e Veterinárias. Jaboticabal Jaboticabal.