Effect of heterologous seminal plasma on the fertilizing capacity of human spermatozoa as assessed by the zona-free hamster egg test

Localization and expression of spermadhesin PSP-I/PSP-II subunits in the reproductive organs of the boar

The epithelial localization and expression of the spermadhesin PSP-I and PSP-II subunits were determined in the testis, ductus epididymes (caput, corpus and cauda), seminal vesicles and bulbourethral glands of mature boars, using immunohistochemical, western blotting and RT-PCR methods. Immunohistochemistry showed positive labelling for PSP-I and PSP-II antibodies in the epithelium of seminal vesicles in all males tested. Positive immunolabelling, but with variable intensity, was also present in the epididymal epithelium (caput, corpus and cauda), although varying largely among segments and boars. Immunoreactivity was nearly or completely absent in the seminiferous epithelium and the bulbourethral gland, although SDS-PAGE and western blotting revealed the presence of PSP-I and PSP-II immunoreactive bands in all the tissue extracts, including the testis and the bulbourethral gland. mRNA amplification by RT-PCR using primers specific for PSP-I and PSP-II showed a trend similar to that observed for western blotting, i.e. intensity variation between tissues (even between segments of the same epididymis) and among boars. Our results indicate that the seminal vesicles are the main source of PSP-I and PSP-II spermadhesins, although epididymal segments, testis and the bulbourethral gland also participate in the expression of both proteins.

Comparative effects of autologous and homologous seminal plasma on the viability of largely extended boar spermatozoa

Sperm handling, associated to artificial reproduction technologies (ART) such as in vitro fertilization (IVF) or the use of flow cytometry for cell analysis or sorting imposes volumetric extension of the sperm suspension and decreases sperm viability, presumably because of the removal of seminal plasma (SP) components. This study evaluated whether a 10% v/v of autologous SP (retrieved from the same donor boar) or homologous SP (e.g. from any of the four fertile boars included, other than the one providing the spermatozoa) would differently affect the viability of boar spermatozoa subjected to large extension in a simple saline medium [phosphate-buffered saline and 0.1% ethylenediaminetetraacetic acid (EDTA), PBSm] to a concentration of 0.3 x 10(6) spermatozoa/ml and incubated for 2 h at 30 degrees C. Sperm viability was monitored as membrane integrity [using the fluorophore carboxyfluorescein diacetate (C-FDA) and propidium iodide (PI)], mitochondrial function (using the fluorophore R-123) and motility characteristics [using Computer Assisted Sperm Analysis (CASA)]. Substraction of the SP and extension followed by incubation in PBSm significantly (p < 0.05) decreased sperm viability, which could be restored by addition of autologous SP. Furthermore, exposure of the extended spermatozoa to homologous SP (from any other individual boar) significantly (p < 0.05) varied with the source of the sire; some boars exerting beneficial effects (even surpassing the effects of the autologous SP; p < 0.05) while at least one boar negatively (p < 0.05) influencing the viability of the incubated spermatozoa. It is concluded that SP should be present when incubating highly extended spermatozoa. As a result of the obvious differences among boars, it would be advantageous to examine the ability of SP to maintain sperm viability prior to the use of SP pools during sperm handling in vitro.

Fertilization failure and dysfunctions as possible causes for human idiopathic infertility

Consideration of the most common currently practiced laboratory assays for human spermatozoal fertility are discussed, with reference to the relevance of such assays to success or failure in human in vitro fertilization (IVF). Such IVF therapy should be the definitive challenge for human spermatozoal fertilization ability. However, when fertilization fails, is polyspermic, or is suboptimal, then questions concerning the step or steps in the process of fertilization which are dysfunctional remain unanswered. Quite possibly new assays need to be devised to address these problems, while in the meantime our present laboratory assay systems need to be improved to discern those defects in fertilization which operate in many cases of human idiopathic infertility.

Absence of correlation between the levels of ATP and other seminal compounds in semen and the results of human in-vitro fertilization

As part of an in-vitro fertilization programme (IVF), semen levels of adenosine triphosphate, fructose, citrate, zinc, free L-carnitine and glycerophosphocholine were measured in 178 men. None of these substances appeared to have any predictive value with regard to the fertilizing potential of the semen during IVF.

Acrosomal enzymes and ultrastructure of unfrozen and cryotreated human spermatozoa

Pooled semen judged to be normal in all parameters was divided into a number of aliquots which were either 1) kept untreated; 2) mixed with glycerol (10% v/v); 3) washed by centrifugation and resuspended to the original volume with buffer; or 4) washed and resuspended in buffer with glycerol (10% v/v). The progressive motility, viability, ultrastructure, and acrosomal enzyme activity (8 different hydrolases) were studied before and after cryotreatment. The described washing procedure effectively removed seminal plasma, and did not alter sperm motility, sperm viability, sperm ultrastructure, or the acrosomal enzymes studied. Glycerol (10%, v/v) had a deleterious effect on most parameters evaluated before cryotreatment. Cryotreatment severely altered the motility and viability of the spermatozoa and their acrosomal morphology but did not cause significant decreases in most of the acrosomal hydrolases measured. However, acrosin/proacrosin levels decreased by 50-80% and were correlated to the acrosomal damage. A simple assay for the measurement of acrosin/proacrosin enzyme levels in whole sperm is presented which could be used as a monitor for acrosomal integrity. No significant differences were seen between the samples cryotreated in the absence or presence of seminal plasma.

Effects of semen fractionation and dilution ratio on equine spermatozoal motility parameters

Two experiments were conducted to examine the effects of semen fractionation and dilution ratio on motility parameters of stallion spermatozoa. In Experiment 1, three ejaculates from each of three stallions were divided into sperm-rich (SR) and sperm-poor (SP) fractions to determine the difference in sperm concentration. Mean sperm concentration in SR fractions (349.5 x 10(6)/ml) was greater (P < 0.001) than that of SP fractions (96.9 x 10(6)/ml). In Experiment 2, three ejaculates from each of two stallions were divided into SR and SP fractions. Fifty percent of the original volume of SR fractions was combined with 50% of the original volume of SP fractions for each ejaculate to represent total ejaculates. SR and total ejaculates were diluted with skim milk-glucose semen extender as follows: 1) no dilution, or dilution to 2) 100 x 10(6)sperm/ml, 3) 50 x 10(6)sperm/ml, or 4) 25 x 10(6)sperm/ml. Semen samples were evaluated at 0.5, 3, 6, 12, and 24 h postejaculation (25 degrees C storage temperature) for percentages of total spermatozoal motility (TSM) and progressive spermatozoal motility (PSM). Mean TSM was greater (P < 0.05) in SR ejaculates than total ejaculates at 12 and 24 h postejaculation. Mean TSM of undiluted semen was lower (P < 0.05) than other dilution ratios over all periods. Mean TSM was greater (P < 0.05) at a 25 x 10(6)sperm/ml dilution ratio than a 50 x 10(6)sperm/ml dilution ratio at 12 and 24 h postejaculation, and greater (P < 0.05) than a 100 x 10(6)sperm/ml dilution ratio from 3 to 24 h postejaculation. Similar patterns were found for PSM. Collection of SR ejaculates and dilution to 25 x 10(6)sperm/ml improved longevity of spermatozoal motility.

In vitro fertilization of hamster and human oocytes by microinjection of human sperm

In this study, swollen sperm heads were obtained after the injection of human sperm into the perivitelline space of hamster oocytes. The number of injected sperm and the sperm concentration in the preincubation medium were found to have an influence on the rate of penetrated hamster oocytes. The optimal injected sperm number was always between five to 12 to obtain 8, 37, and 36% penetration for donors A, B, and C, respectively. The optimal sperm concentration in preincubation medium was between 6 and 22 x 10(6) sperm/ml to obtain 16, 47, and 43% penetration for donors A, B, and C, respectively. The rate of polyspermic oocytes was related to the injected sperm number (0, 55, and 100% for one to four, five to 12, and more than 12 injected sperm respectively). Ten human mature oocytes were injected with the sperm from six normal donors. Five fertilized eggs were obtained, and of these four cleaved in in vitro culture.