Semen

About: Semen is a research topic. Over the lifetime, 14571 publications have been published within this topic receiving 407739 citations. The topic is also known as: come & ejaculate.

Impact of cryopreservation and reactive oxygen species on DNA integrity, lipid peroxidation, and functional parameters in ram sperm.

Abstract: Assisted reproduction using frozen-thawed semen has practical advantages, although cryopreservation is detrimental to sperm fertility in most mammals We examined the influence of cryopreservation and reactive oxygen species (ROS) on ram sperm DNA stability (using SCSA), lipid peroxidation (LPO), chlortetracycline fluorescence (CTC) patterns, motility and viability In Experiment 1, DNA integrity, LPO, CTC, motility and viability tests were performed on fresh and cryopreserved sperm after 0, 6, and 24 hr in synthetic oviductal fluid (SOF) In Experiment 2, fresh sperm were incubated in serum-free SOF (SOF-S; 1, 4, and 24 hr) with 0, 50, 150, or 300 microM H2O2 then assayed Cryopreservation increased the percentage of sperm with a high DNA fragmentation index (%DFI), decreased the percentages of motile and viable sperm at thawing (0 hr), but did not affect LPO H2O2 (150 or 300 microM) increased %DFI after 24 hr LPO or sperm viability were not affected by H2O2, although most motility parameters decreased H2O2 decreased the percentage of chlortetracycline pattern F sperm at 4 hr and increased the percentage of acrosome-reacted sperm (pattern AR) after 1 hr Pooled data of Experiment 2 showed LPO was positively correlated with SCSA (r = 029 to r = 059; P < 005 to P < 001), while most motility parameters and the percentage of viable sperm were negatively correlated with LPO (r = -030 to r = -038; P < 005 to P < 001) LPO was positively correlated with the percentage of pattern AR sperm (r = 033; P < 001) Cryopreservation and H2O2 promote DNA instability in ram sperm, though motility is a more sensitive indicator of oxidative stress than the other parameters investigated

Isolation of motile spermatozoa by density gradient centrifugation in Percoll

Abstract: A procedure using centrifugation in density gradients composed of Percoll was developed for isolation of spermatozoa from mammalian semen. To evaluate the technique, rabbit, human, or bovine semen was layered over continuous Percoll gradients ranging in density from 1.02 to 1.13 gm/ml and centrifuged at 1,500g for 45 min. After centrifugation, the seminal plasma remained above the gradient, whereas the spermatozoa and seminal particles were distributed within the gradient according to their buoyant densities. Unlike most washing techniques, no sperm pellet was formed; instead, the spermatozoa were concentrated into a compact band above the most dense layer of Percoll. The spermatozoa recovered from the gradient were easily resuspended by gentle techniques. Thus, the mechanical stress to the spermatozoa was minimized. Osmotic stress to the spermatozoa was also negligible as the Percoll gradients were isotonic throughout. Spermatozoa obtained by this technique possessed motility equivalent to that of spermatozoa in the unfractionated semen. Sperm suspensions recovered from the gradients contained less than 5% of the nonspermatozoal particles present in the original samples of unfractionated semen. Soluble seminal components were also efficiently removed from the spermatozoa. Thirty billion bovine spermatozoa could be fractionated on a single gradient without loss of effectiveness. Recovery of spermatozoa from these preparative separations averaged 80%. These results demonstrated that Percoll was a superior medium for efficient density gradient isolation of motile spermatozoa free of contamination by other seminal constituents.

The presence of bacteria species in semen and sperm quality.

Abstract: To verify the prevalence of semen bacterial contamination and whether the contamination could decrease sperm quality. Spermiogram, semen culture, and sperm transmission electron microscopy (TEM) analysis were performed. TEM data were elaborated using a mathematical formula that calculates a fertility index (FI)—able to define patients as fertile or infertile—and the percentage of sperm apoptosis, immaturity and necrosis. We aligned the amino acid sequence of beta-tubulin with protein of the most frequent species isolated from semen. Patients were divided according to the contaminating species; in each group, we observed fertile individuals, in whom the semen quality was similar to that of controls and infertile men whose sperm quality was significantly decreased, in terms of motility, FI, apoptosis and necrosis. Partial homology between β-tubulin and bacterial proteins was observed. Sperm bacterial contamination is quite frequent and could contribute to the deterioration of the sperm quality of infertile men.