Morphology and X-ray microprobe analysis of spermatozoa from fertile and infertile men in in vitro fertilization

Zinc is sufficiently abundant within mammalian sperm nuclei to bind stoichiometrically with protamine 2

Although studies have demonstrated that zinc can bind to sperm nuclear proteins, specifically protamine 2, it has not been shown that the metal is sufficiently abundant inside the sperm nucleus to interact stoichiometrically with these proteins. In this study proton-induced X-ray emission (PIXE) has been used to measure the amount of sulfur and zinc within the nuclei of individual sperm cells to infer the stoichiometry of zinc binding to protamine 2 in six species of mammal: bull, chinchilla, stallion, hamster, human, and mouse (protamine 2 comprises from 0% (bull) to 67% (mouse) of the protamine present in the sperm of these animals). Using the sulfur mass and electrophoretic data on the relative proportion of protamine 1 and protamine 2 in the sperm chromatin of these species, the protamine 1, protamine 2, and total protamine contents within each species sperm nuclei have been determined. The PIXE measurements reveal that the zinc content of the sperm nucleus varies proportionately with the protamine 2 content of sperm chromatin. PIXE analyses of hamster protamines extracted under conditions that appear to at least partially preserve zinc binding also confirm that the majority of the metal is bound to protamine. In five of the species examined, sufficient zinc is present for each protamine 2 molecule to bind one zinc. The results obtained for chinchilla sperm, conversely, indicate the chinchilla protamine 2 molecule may interact differently with zinc. Chinchilla sperm only contain enough zinc for one atom to be bound to two protamine 2 molecules.

The evaluation of morphological abnormalities of human spermatozoa in fertile and infertile men

Spermatozoal morphology in semen from 114 fertile men, 107 infertile men with varicocele and 35 infertile men with infection of the accessory genital organs, aged from 18 to 53 years were evaluated by Papanicolaou-stained smears in order to investigate: (a) the frequency of abnormalities in the neck and tail of spermatozoa with an abnormal head and (b) the ability of prediction of the morphology of one sperm part when the morphology of another part is known. The investigation showed that: (1) morphological abnormalities in the neck are significantly higher (P < 0.001, P < 0.01), when the head was abnormal, compared to spermatozoa with a normal head in fertile men and in men with varicocele, respectively; (2) morphological abnormalities in the tail are also higher (0.05 < P < 0.1) in spermatozoa with an abnormal head in men with infection; (3) the proportional reduction of error (PRE) was low in all cases. Our results show that spermatozoa with abnormal heads more often present morphological abnormalities of their counterparts compared to spermatozoa with normal heads. Nevertheless, no prediction can be made on the nature of the morphology of a part of a spermatozoon on the basis of knowledge of its morphology of another part.

Coexistence of spermatozoa morphological abnormalities in the semen of potentially fertile men

Spermatozoal morphology in semen specimens from 114 potentially fertile men, aged from 20 to 40 years, was evaluated from Papanicolaou stained smears, in order to investigate: (a) the frequency of abnormalities in the neck and tail of spermatozoa with an abnormal or normal head, and (b) the ability of prediction of the morphology of one sperm part when the morphology of another is known. It was found that: (1) Morphological abnormalities in the neck are significantly higher (p less than 0.001) in spermatozoa with an abnormal head than in spermatozoa with a normal head. (2) Morphological abnormalities in the tail and cytoplasmic droplet are also higher, although not significant, in spermatozoa with an abnormal head. (3) The proportional reduction in error (PRE) was low in all cases. Our results show that spermatozoa with abnormal heads more often present morphological abnormalities of their other parts than spermatozoa with normal heads. However, no prediction can be made on the nature of the morphology of a part of a spermatozoon on the basis of knowledge of the morphology of another of its parts.

Pixe analysis of reproductive fluids

An external 3.8-MeV proton beam was employed to induce X-rays in 100-mg pellets of human follicular fluids and in 4-8 mg pellets of spermatozoa. The elements Cl, K, Ca, Fe, Cu, Zn, and Br were quantitatively determined in follicular fluids, whereas the elements, S, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Ni, Cu, and Zn were determined in the spermatozoa. Both samples had high interelement Spearman correlation coefficients. Correlations of elements in the samples were observed with several clinical parameters. The multielemental analysis of spermatozoa can be used to approximate quantities of trace elements inserted into the egg ooplasm at the time of fertilization. These elemental quantities appear to be in the femtogram (10(-15)) range.