Changes in rat spermatozoa lipids and fatty acids during epididymal maturation

ZANETTI SR; MONCLUS MA; AVELDAÑO MI; FORNÉS MW

Rosario, Santa Fe, Argentina

Congreso; XLII Reunion Anual de la Soc. Argentina de Investigación en Bioquímica y Biología Molecular; 2006

Soc. Arg. de Investigación en Bioquímica y Biología Molecular

CHANGES IN RAT SPERMATOZOA LIPIDS DURING EPIDIDYMAL MATURATION Zanetti SR#; Monclus MA§; Aveldaño MI# and Fornés MW§ IHEM, CONICET-UNC, 5500 Mendoza (§) e INIBIBB, CONICET-UNS, 8000 Bahía Blanca (§), Argentina. During their epididymal transit spermatozoa undergo a series of maturational changes that render them capable of fertilization. Here we focused on the changes undergone by major lipid classes and fatty acids. The cholesterol (Ch) and phospholipids (PL) content decreased with epididymal maturation, the Ch/PL ratio increasing from 0.22 to 0.30 from caput to cauda epididymidis. The neutral glycerolipid content was also significantly larger in caput than in cauda spermatozoa. The most pronounced change observed in glyceroPL and neutral glycerolipid fatty acids occurred in the proportion of 22:4n-9. The percentage of this fatty acid increased 1.7-fold in the GPL and 1.5 fold in the 1-O-alkyl-2,3-diacylglycerols, respectively, with sperm maturation.  The content of sphingomyelin (SM), lipid that in previous work was shown to be typically rich in very long chain polyunsaturated fatty acids (VLCPUFA) in germinal cells from the rat testis, also decreased. The proportion of SM-associated VLCPUFA such as 28:4n-6 tended to decrease in SM and to increase in ceramide with sperm maturation. The marked alterations spermatozoa undergo during their epididymal transit in lipid and fatty acid profile may lead to changes in the biophysical properties that are optimal in determining the physiological functions of these gametes.