Desenvolvimento, caracterização e avaliação de lipossomas contendo β-sitosterol em um modelo experimental ex vivo de cataratogênese

Abstract

Cataracts, the main cause of blindness worldwide, is due to cloudiness in the eye lens, as a result of oxidative stress, loss of chaperone function of crystallin proteins and other factors that trigger their precipitation. The present study evaluated the effect of -sitosterol in preventing cataract using an ex vivo model of cataractogenesis. -Sitosterol loaded liposomes (BSL) were developed, prepared by the modified reverse phase method and evaluated for mean diameter (MD), polydispersion index (PDI), zeta potential (ZP), as well as morphological aspects by scanning electron microscopy (SEM-FEG). The anticataratogenic activity of BSL was studied in an ex vivo lens culture model of Wistar rats supplemented with sodium selenite. Lenses were photographed before and after culture. Lens opacity (transmittance) was determined using a UV-Vis spectrophotometer and structural changes in proteins were determined by Raman spectroscopy. The BSL had a mean diameter of 183.90  15.41 nm, a PDI of 0.319  0.01 and a ZP of -31.25  0.63 mV. The photographs showed that BSL slowed the progression of opacity, and the transmittance spectra of lenses incubated with BSL showed attenuation in the reduction in transmittance induced by sodium selenite. Raman spectroscopy revealed increases and decreases in microenvironments of tryptophan residues in induced lenses and variation in amide intensity. Treatment with BSL allowed to maintain the foldable structure of the crystalline β-leaf, suggesting a therapeutic option for preventing cataract formation. The development of nanostructured systems loaded with potential therapeutic compounds and their spectroscopic evaluation can provide information about possible treatments for cataracts.