THE FATTY-ACID COMPOSITION OF PHOSPHOLIPIDS OF SPERMATOZOA FROM INFERTILE PATIENTS

The lipid composition of the sperm membrane has a significant effect u pon the functional characteristics of spermatozoa. In the present stud y we investigated the fatty acid (FA) composition of subpopulations of spermatozoa separated on a discontinuous Percoll gradient (47:90%) an d the FA composition of phospholipids (PL) of sperm heads and tails in both normal and abnormal semen samples. In normozoospermic samples, p olyunsaturated fatty acids (PUFA) represented 34.0 +/- 1.3 (mean +/- S E, mole %) and 25.6 +/- 1.2% of total FA of PL of the 47 and 90% Perco ll fractions respectively. Docosahexaenoic acid (22:6 omega 3, DHA) co ntributed to more than 60% of total PUFA. DHA was significantly lower in both the 47% (P < 0.05) and the 90% (P < 0.01) Percoll fractions of oligozoospermic samples and in the 90% Percoll layer of asthenozoospe rmic samples (P < 0.01), compared with normozoospermic samples. The om ega 6/omega 3 ratio was significantly increased in both Percoll fracti ons of samples with oligozoospermia (47%, P < 0.001 and 90%, P < 0.001 ) or with asthenozoospermia (47%, P < 0.05 and 90%, P < 0.001) compare d with normozoospermic samples. The oxidative potential index (OPI) of spermatozoa recovered from the 47% Percoll layer was significantly hi gher (P < 0.0001) than of those recovered from the 90% Percoll. Mean m elting point (MMP), an index of membrane fluidity, was significantly l ower in head than in tails (P < 0.01) of spermatozoa, and also in both the 47% (P < 0.01) and 90% (P < 0.001) Percoll fractions of normozoos permic samples in comparison with oligozoospermic samples. The MMP was significantly higher (P < 0.05) in samples of patients with idiopathi c oligo/asthenozoospermia, varicocele, and male accessory gland infect ion (MAGI). These differences in FA composition of Fl, in subpopulatio ns of human spermatozoa, and in their heads and tails may be related t o sperm maturity and to differences in physiological function.