Durante la capacitación y la reacción acrosomal ocurren cambios que afectan los lípidos y ácidos grasos del espermatozoide de rata

ZANETTI SR; MONCLUS MA; RENSETTI DE; FORNÉS MW; AVENDAÑO M

Huerta Grande , Córdoba

Congreso; I Reunión Conjunta de Sociedades de Biología de la República Argentina; 2007

Sociedades de Biología, Cuyo, Córdoba, tucuman, Rosario y Bs. As.

Changes affecting rat spermatozoal lipids and fatty acids during capacitation and the acrosome reaction Zanetti S, Monclus M, Rensetti D, Fornés M  and Aveldaño M IHEM, CONICET-UNC, 5500 Mendoza, e INIBIBB, CONICET-UNS, 8000 Bahía Blanca, Argentina. e-mail: szanetti@criba.edu.ar Mammalian spermatozoa must mature, capacitate and undergo the acrosome reaction (AR) as prerequisites to fertilize an egg. In this work we focused on the changes specific lipids and fatty acids of mature rat spermatozoa undergo during these processes. Capacitation was induced by incubation in a chemically defined medium containing BSA and the AR by the inclusion of a Ca2+ ionophore. Capacitation resulted in a significant efflux of cholesterol from the cells to the BSA-containing medium, paralleled by a partial decrease in lipid phosphorus per cell. During the AR, the content of lipid P (mostly glycerophospholipids) decreased even more, concurrently with the production of diacylglycerols, phosphatidic acid, lysophospholipids and free fatty acids. The content of sphingomyelin also decreased, being mostly recovered as ceramide. The fatty acid composition of the produced lipid metabolites suggest that they result from activation of specific phospholipases, including a sphingomyelinase. The accumulation of these potentially fusogenic lipids in acrosome-reacted spermatozoa suggest these metabolites play a role in producing a sperm membrane able to undergo fertilization-related fusion events.