Adverse effects of peroxidized lipid on human spermatozoa.

Peroxidation of the sperm cells’ own phospholipids, closely bound up with declining motility, has been demonstrated in human spermatozoa; the rate of peroxidation was determined quantitatively by the reaction with thiobarbituric acid. Immotile or poorly motile spermatozoa from necrospermic or oligospermic semen exhibited a higher rate of peroxidation than highly motile spermatozoa from normal ejaculates. Peroxidized unsaturated fatty acids added to washed sperm suspensions immobilized the spermatozoa rapidly and permanently. Human seminal plasma was found to contain a non-ultrafiltrable factor which effectively prevented, but did not reverse, the toxic effect upon spermatozoa of either endo­ genous or exogenous lipid peroxides.