Disturbances of sperm flagella due to failure of epididymal maturation and their possible relationship to phospholipids.

A recent classification of alterations of midpiece and flagellum describes the phenomenon of abnormal staining behaviour of human sperm flagella during Papanicolaou and Shorr staining. In these techniques, human sperm tails normally stain red; however, if epididymal function is disturbed, the flagella appear bluish, while they are devoid of other recognizable defects. Such spermatozoa were shown to be immotile, the motility disturbance being referred to as epididymal dysfunction. To define the physiological substrates of this descriptive phenomenon, caput spermatozoa from 10 epididymides of five patients who had undergone orchiectomy because of prostatic cancer were investigated. These spermatozoa showed severe motility disturbances, and almost all their flagella stained atypically. Attempts to stimulate such spermatozoa by pentoxifylline achieved a slight improvement in motility. However, addition of seminal plasma from fertile donors resulted in a significant improvement in motility, accompanied by an increase in the number of normally stained flagella. Even better results were achieved by incubation with liposomes made from soybean lipids, mainly phosphatidylcholine. It is concluded that poor motility and atypical staining behaviour of human caput sperm tails can at least partly be related to a lack of phospholipids in the flagellar membrane. Substitution of phospholipids may be a therapeutic approach in procedures using caput spermatozoa, although in addition to the improvement of sperm motility, the enhancement of fertilizing capacity remains to be established.