DSC characterization of rabbit corneas treated with Stryphnodendron adstringens (Mart.) Coville extracts

Abstract

© 2017, Akadémiai Kiadó, Budapest, Hungary.Keratoconus is an eye ectasia that affects the cornea causing distortion of vision. Corneal crosslinking promoted by riboflavin photo-stimulated at 365 nm is a treatment used successfully to block the keratoconus progression. In this study, we characterize rabbit corneas subjected to enhanced crosslinking using different vegetable extracts prepared from Stryphnodendron adstringens (Mart.) Coville bark by differential scanning calorimetry. The extracts tested in this study were: aqueous, ketonic, ethanolic, ethyl acetate and hydroalcoholic, which revealed high levels of polyphenols, such as proanthocyanidins. The corneas, obtained from the slaughter rabbits, were divided into groups: control (consisting of untreated corneal samples) and S. adstringens, where the samples were subjected to 4% vegetable extracts for 2 h. The DSC profiles of the corneas were obtained in nitrogen atmosphere. The results showed that temperature and enthalpy of denaturation of the corneal samples treated with S. adstringens were higher than the control group. The control group presents temperature and enthalpy values of 59.8 ± 1.1 °C and 24.6 ± 2.7 J g−1, respectively. After crosslinking with ketone extract, the values were 90.1 ± 1.1 °C and 39.9 ± 2.7 J g−1. These results show that S. adstringens is efficient to increment the crosslinking level of the corneas.