The mechanisms responsible for mediating the influence of sperm preparation protocols on human sperm function have been investigated. Techniques that involved the separation of motile spermatozoa prior to centrifugation were found to yield sperm suspensions of highest quality. If the spermatozoa were centrifuged prior to isolation of the motile cells, sperm function was impaired. The detrimental effects of centrifugation were associated with a sudden burst of reactive oxygen species production by a discrete subpopulation of cells (characterized by significantly diminished motility and fertilizing capacity) that could be separated from normal functional spermatozoa on Percoll gradients. If unfractionated sperm suspensions were subjected to centrifugation, the reactive oxygen species generated by this subpopulation impaired the functional competence of normal spermatozoa in the same suspension. Assessment of the ability of the antioxidants, butylated hydroxytoluene, and vitamin E, to curtail the peroxidative damage inflicted by such cells in response to centrifugation revealed a significant improvement of sperm function in the presence of vitamin E.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.1939-4640.1988.tb01067.x

Significance of Reactive Oxygen Species and Antioxidants in Defining the Efficacy of Sperm Preparation Techniques

In 1992 Carlsen et al. reported a significant global decline in sperm density between 1938 and 1990 [Evidence for Decreasing Quality of Semen during Last 50 Years. Br Med J 305:609-613 (1992)]. We subsequently published a reanalysis of the studies included by Carlsen et al. [Swan et al. Have Sperm Densities Declined? A Reanalysis of Global Trend Data. Environ Health Perspect 105:1228-1232 (1997)]. In that analysis we found significant declines in sperm density in the United States and Europe/Australia after controlling for abstinence time, age, percent of men with proven fertility, and specimen collection method. The declines in sperm density in the United States (approximately 1.5%/year) and Europe/Australia (approximately 3%/year) were somewhat greater than the average decline reported by Carlsen et al. (approximately 1%/year). However, we found no decline in sperm density in non-Western countries, for which data were very limited. In the current study, we used similar methods to analyze an expanded set of studies. We added 47 English language studies published in 1934-1996 to those we had analyzed previously. The average decline in sperm count was virtually unchanged from that reported previously by Carlsen et al. (slope = -0.94 vs. -0.93). The slopes in the three geographic groupings were also similar to those we reported earlier. In North America, the slope was somewhat less than the slope we had found for the United States (slope = -0.80; 95% confidence interval (CI), -1.37--0.24). Similarly, the decline in Europe (slope = -2.35; CI, -3.66--1.05) was somewhat less than reported previously. As before, studies from other countries showed no trend (slope = -0.21; CI, -2.30-1.88). These results are consistent with those of Carlsen et al. and our previous results, suggesting that the reported trends are not dependent on the particular studies included by Carlsen et al. and that the observed trends previously reported for 1938-1990 are also seen in data from 1934-1996.

/pdf/the-question-of-declining-sperm-density-revisited-an-1mxyi8ogs6.pdf

The question of declining sperm density revisited: an analysis of 101 studies published 1934-1996.

Asthenospermia is the main factor of male infertility among patients consulting the Asir Infertility Center in Abha, Saudi Arabia. Lipid peroxidation occurring in both the seminal plasma and spermatozoa was estimated by malondialdehyde (MDA) concentration. Spermatozoal MDA concentration was higher in men with decreased sperm motility. The MDA concentration in the seminal plasma exhibited no relationship with sperm concentration, sperm motility, the number of immotile spermatozoa, or even the absence of spermatozoa. The MDA concentration in sperm pellet suspensions of asthenospermic and oligoasthenospermic patients was almost twice that of the normospermic males. The MDA concentration in the sperm pellet suspension from normospermic or oligospermic patients was about 10% that in the seminal plasma. However, the MDA concentration in the sperm pellet suspension of asthenospermic or oligoasthenospermic patients was about 15% that in the seminal plasma. Treatment of asthenospermic patients with oral Vitamin E significantly decreased the MDA concentration in spermatozoa and improved sperm motility. Eleven out of the 52 treated patients (21%) impregnated their spouses; nine of the spouses successfully ended with normal term deliveries, whereas the other two aborted in the first trimester. No pregnancies were reported in the spouses of the placebo-treated patients.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/j.1939-4640.1996.tb01830.x

Lipid Peroxidation and Human Sperm Motility: Protective Role of Vitamin E

Intrauterine insemination: a critical review.

Effect of the total motile sperm count on the efficacy and cost-effectiveness of intrauterine insemination and in vitro fertilization

The improved ten-micrometer chamber for rapid sperm count and motility evaluation.

A simple apparatus to collect moving sperm by non-traumatic means which can be used for artificial insemination is described. The technique is based on enhancing the process of migration from the seminal fluid into a top-layered artificial medium in an ordinary test tube. This has been achieved by controlling 3 main variables: 1) The dilution of migrated sperm was minimize by using only 0.5 ml of the medium layered onto 1 ml semen; 2) increasing the surface area between these media by turning the test tube from a vertical to almost a horizontal position; 3) stimulating sperm activity by incubation at 37 degrees C under air: 5% CO2 for 30 min. When restored to a vertical position approximately 0.3 ml medium, sufficient for most AIH or IVF procedures, was gently aspirated. The effects of these variables on the rate of sperm migration was tested one at a time, and increments that ranged from 20% to as much as 10-fold were detected. When these 3 variables were optimized and 58 semen specimens analyzed, it was found that motility increased from 42 to 87%, velocity from 24.5 to 27.3 micron per sec, whilst abnormal forms dropped from 37 to 15%. The final concentration of motile sperm was 23 X 10(6)/ml compared to an original mean concentration of 34 X 10(6)/ml, indicating a relative recovery of 68%. Oligoasthenospermic specimens revealed similar changes in sperm motility, velocity, morphology and recovery. However, due to the low initial content of moving sperm (4.8 X 10(6)/ml), their final concentration was also low (2.7 X 10(6)/ml). Such specimens required additional preliminary preparation to increase the sperm concentration prior to the migratory procedure.

Improved techniques for collecting motile spermatozoa from human semen. I. A self-migratory method.

A simple and atraumatic method for concentrating washed, motile spermatozoa from normal and subnormal semen specimens is described. It incorporates a modified technique of centrifugation in which sperm are spun onto a soft, fluid cushion, thereby minimizing mechanical damage. Following initial semen dilution to 5-10 ml in an artificial medium, the mixture is transferred to a test tube and layered onto 1 ml of oily contrast medium (Lipiodol). After centrifugation at 300 g for 10 min all but 0.5 ml of the supernatant is discarded, and the unshaken test tube is incubated at 37 degrees C for 15-20 min, during which time the motile sperm migrate into the upper 0.5 ml. After this incubation, 0.3 ml of the upper layer is removed which is sufficient for most IVF and AIH purposes. It contains concentrated, washed, motile spermatozoa that are free of debris and most abnormal forms. No change in pH or osmolarity and no diffusion of any iodine from the oil base into the top layer were detected.

Amnon Makler

Papers

The improved ten-micrometer chamber for rapid sperm count and motility evaluation.

Improved techniques for collecting motile spermatozoa from human semen. I. A self-migratory method.

Improved techniques for separating motile spermatozoa from human semen. II. An atraumatic centrifugation method.

Factors affecting sperm motility. IX. survival of spermatozoa in various biological media and under different gaseous compositions.

A device for injecting and retaining a small volume of concentrated spermatozoa in the uterine cavity and cervical canal.