Sperm plasma membrane

About: Sperm plasma membrane is a research topic. Over the lifetime, 1016 publications have been published within this topic receiving 49964 citations.

The effect of two packaging systems on the post-thaw characteristics of canine sperm

Abstract: The aim of this study was to compare the effect of different packaging systems on some parameters of cryopreserved canine spermatozoa. The experimental material consisted of the sperm-rich fractions of ejaculates collected from four Beagle dogs. Semen samples for cryopreservation were stored in 0.25 ml plastic straws and two aluminum tubes with a total volume of 5.0 ml. Semen was frozen in static nitrogen vapor for 10 minutes (0.25 ml straws) or 15 and 20 minutes (aluminum tubes). Post-thaw assessments involved the determination of sperm motility parameters using a computer assisted sperm analyzer (CASA), sperm plasma membrane integrity (SPMI), mitochondrial membrane potential (MMP) and acrosome integrity (normal apical ridge, NAR). Regardless of the packaging system applied, no significant differences in total sperm motility (TMOT) or selected kinematic parameters were observed after freezing-thawing. However, spermatozoa frozen in 0.25 mL straws were characterized by improved functionality, in particular mitochondrial function, after thawing. The results indicate that large quantities of canine semen can be frozen in aluminum tubes. Further studies are required, however, to evaluate different freezing and thawing rates of aluminum tubes.

Comparative study of different methods for plasma membrane integrity assessment of frozen-thawed boar spermatozoa

Abstract: In this study, different assays were used to assess the structural and functional integrity of the sperm plasma membrane following freezing-thawing of the whole ejaculates (WEs) and sperm-rich fractions (SRFs) of boar semen. Besides sperm viability assessments (motility and mitochondrial membrane potential using a mitochondrial specific dye, JC-1 with propidium iodide, PI), sperm plasma membrane integrity (PMI) assessments were determined simultaneously using different membrane-based tests (SYBR14/PI and carboxyfluorescein diacetate (CFDA) with PI (CFDA/PI), and the hypo-osmotic swelling (HOS) test). ANOVA results showed that boar variability had a significant effect on the analysed parameters of post-thaw sperm characteristics. Spermatozoa harvested from the WEs exhibited a marked decline in post-thaw viability, manifested in reduced motility and mitochondrial membrane potential, than those originated from the SRFs after freezing-thawing. Cryopreservation compromised sperm PMI, as indicated in a significant decline in SYBR-stained, CFDA-stained or HOS-positive sperm cells, irrespective of the ejaculate collection procedure. It was observed that the membrane-based tests were strongly inter-correlated. Furthermore, agreement between the measurements of the membrane-based tests was confirmed by the Bland-Altman scatter plots of differences, suggesting that these tests could detect the same sperm cohorts, which were susceptible to cryo-induced membrane damage. The findings of this study indicate that dual fluorescent staining with SYBR-14/PI and CFDA/PI assays, in combination with the HOS test, provide more precise description of the sperm populations in frozen-thawed boar semen.

Effect of Sources and Concentrations of Soybean Phosphatidylcholine on Diluted Goat Semen Equilibrated at 4

Abstract: The objective of the present study was to determine the proper sources and concentrations of soybean lecithin (phosphatidylcholine, PC) to be used as substitute for hen egg yolk in extender for preserving goat semen. Two sources of soybean lecithin (20% and 95% soybean phosphatidylcholine; PC20 and PC95) and three concentrations (1%, 2% and 3% v/v) of PC20 and PC95 supplemented in Tris-citric acid-fructose (TCF) extender were tested. The TCF extender supplemented with 20% hen egg yolk was used as a control. Fresh semen samples were collected from 3 goats by artificial vagina. Seminal plasma was removed by centrifugation and sperm pellets were pooled together and divided into 7 groups according to types of extender. The diluted semen samples were kept at 4 ℃ (equilibration). The semen qualities including progressive motility, sperm viability, sperm plasma membrane integrity and tail abnormalities were evaluated before dilution and after 4 hrs equilibration. It was found that the progressive motility of equilibrated semen in egg yolk and PC20 extenders were higher than those in PC95 extender (P ＜ 0.05). Sperm viability was lower in 1% and 2% PC95 extender compared to other extenders (P ＜ 0.05). PC20 extender maintained the sperm membrane integrity and normal tail morphology at low temperature better than egg yolk and PC95 (P ＜ 0.05). It can be concluded that 20% soybean phosphatidylcholine supplemented in TCF extender at 1%-3% (v/v) is as effective as hen egg yolk to preserve goat semen during equilibration at 4 ℃ for 4 hrs.

Male infertility: Role of vitamin D and oxidative stress markers

Abstract: Spermatozoa are vulnerable to oxidative stress because of their inherent reduced antioxidant defence and DNA repair mechanisms. Polyunsaturated fatty acids in sperm plasma membrane break down to cytotoxic lipid aldehyde, 4-Hydroxynonenal, whereas 3-Nitrotyrosine is generated by peroxynitrite induced tyrosine nitration. Both oxidative stress markers contribute to altered sperm function and infertility. Vitamin D, a membrane antioxidant, has a potential scavenger capacity. We compared oxidative stress markers and vitamin D in male subjects with normal and altered sperm parameters and explored association of these markers: 4-Hydroxynonenal and 3-Nitrotyrosine with Vitamin D. Higher 4-Hydroxynonenal levels in altered sperm parameter group and a negative correlation with sperm count, motility and morphology (p < 0.001) was observed. Vitamin D serum concentration in altered sperm parameters was less (p = 0.016) showing a significant positive correlation with sperm count and morphology. 4-Hydroxynonenal was significantly higher in altered sperm parameters showing negative correlation with vitamin D. Highest serum concentrations of 4-Hydroxynonenal were observed in vitamin D-deficient subjects. Significantly higher concentration of 4-Hydroxynonenal was estimated in altered sperm parameters of vitamin D sufficient group (p < 0.001). This suggests 4-Hydroxynonenal as an oxidative stress marker leading to altered sperm function and infertility with some association with vitamin D; needs to be explored.