Changes in rat spermatozoa sphingolipids during epididymal maturation and acrosome reaction

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

XXVI Reunión Científica Anual de la Sociedad de Biología de Cuyo.

Congreso; XXVI Reunión Científica Anual de la Sociedad de Biología de Cuyo; 2006

Sociedad de Biología de Cuyo

During their epididymal transit spermatozoa undergo a series of changes –maturational and capacitated changes_- befote they can undergo the acrosome reaction (AR) that enable them to fertilize an egg. The mechanism underlaying these events have not yet been fully elucidated. In this work we focused on their effects on the amounts of fatty acids composition of the mains sphingolipids class of  mature rat spermatozoa. Sphingomyelin (SM) and ceramide (Cer) , lipids taht in previous Works were shown to be tipically rich in very long chain   polyunsaturated fatty acids (VLCPUFA) in germinal cells from the rat testis, changad with epididymal maturation . The content of SM decreased but Cer increased, so the ratio Cer/SM increased from capuz to cauda epididymis, suggesting the activation of a sphingomyelinase. The proportion of SM-associated VCLPUFA such as 28:4n-6 tended to decrease in SM and to increase in Cer with sperm maturation. Capacitation was assessed by protein tyrosine phosphorylation assay and AR was induced by stimulation with A23187/CAE+    in the presence of albumin. Capacitation resulted in a significant increase of SM and Cer, both increased additionally in acrosome-reacted-spermatozoa did the male germ cell specific sulphogalactolipid (seminolipid), SM and Cer being richer than those of the starting cells in VCLPUFA, both non-hydroxylated  and 2-hydroxylated. The sphingolipid changes may work synergistically with protein phosphorylation to convert an initially stable to a fuse-competent membrane, capable to engaging in the AR