Aplicación de microscopía Raman al análisis de cambios estructurales en la zona pelúcida de ovocitos bovinos durante la maduración in vitro

JIMÉNEZ, LE; BENÍTEZ, L; RIZO, G.; MARIELA ROLDÁN OLARTE; ALVAREZ, RMS

Santiago del Estero

Congreso; XLIV Reunión de la Sociedad Argentina de Biofísica; 2015

Sociedad Argentina de Biofísica

It is known that sialic acid is one of the main components of glycoproteins present in oocyte zona pellucida. Experimental data suggest that sialic acid would be responsible for mediating the sperm-zona pellucida interaction, as well as it would be involved in the block to polyspermy (1). The aim of this study was to determine if the maturation process affects the overall structural conformation of zona pellucida. We are particularly focused in the evaluation of the spectral changes related to sialic acid content/microenvironment in order to associate them with its proposed functions. We compared the Raman spectra of bovine oocytes zona pellucida in two stages: immature (IMM) and in vitro matured (IVM). Identification and assignment of the main glycoprotein bands were performed. Special attention was paid to the sialic acid bands based on computer calculations at the B3LYP/6-311 ++g* level of theory. Geometry optimization and the subsequent vibrational prediction of a single sialic acid molecule allow associating the band observed at 873 cm-1 in the experimental spectra to the glycerol group.Spectral data are complemented with statistical studies (discriminant analysis). Based on these results we conclude that the sialic acid is a good variable to differentiate between these two bovine oocyte developmental stages.