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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.
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TL;DR: This protein can be distinguished from other previously characterized seminal plasma proteins and it is assumed that this protein is responsible for delaying uptake of calcium into ejaculated sperm by altering a component(s) of the sperm plasma membrane which serves to actively transport calcium into these cells.
105 citations
TL;DR: It is demonstrated that cholesterol induced a stabilization of the plasma membrane in rainbow trout spermatozoa, but this stabilization before cryopreservation brought no improvement to the poor freezability of this cell.
Abstract: During cryopreservation, the cell plasma membrane faces severe perils, including lipid phase separation, solute effects, and osmotic stresses associated with ice crystallization. How the initial biophysical properties of the plasma membrane can be modulated before cryopreservation in order to influence cellular resistance to the freeze-thaw stress is addressed in this study. Rainbow trout (Oncorhynchus mykiss) spermatozoa were chosen because the lack of an acrosome in this species suppresses potential interactions of cryopreservation with capacitation. Methyl-beta cyclodextrin-induced modulation of membrane cholesterol revealed the presence of a significant cholesterol exchangeable pool in the trout sperm plasma membrane, as membrane cholesterol content could be halved or doubled with respect to the basic composition of the cell without impairing fresh sperm motility and fertilizing ability. Biophysical properties of the sperm plasma membrane were affected by cholesterol changes: membrane resistance to a hypo-osmotic stress increased linearly with membrane cholesterol whereas membrane fluidity, assessed with DPH (1,6-diphenyl-1,3,5-hexatriene) and with several spin-labeled analogues of membrane lipids, decreased. Phosphatidyl serine translocation between the bilayers was slowed at high cholesterol content. The increased cohesion of fresh trout sperm plasma membrane as cholesterol increased did not improve the fertilizing ability of frozen-thawed sperm whereas the lowest cholesterol contents impaired this parameter of sperm quality. Our study demonstrated that cholesterol induced a stabilization of the plasma membrane in rainbow trout spermatozoa, but this stabilization before cryopreservation brought no improvement to the poor freezability of this cell.
105 citations
TL;DR: In this paper, rat sperm viability was assessed with SYBR-14 and PI and sperm mitochondria were differentially labeled with JC-1, and the percentage of spermatozoa staining orange was highly correlated with expected sperm viability.
104 citations
TL;DR: Since there is no linear correlation between sperm quality and pregnancy rates, an improvement in semen parameters should not be the sole outcome considered in studies of antioxidant therapies, and more multicentre, double-blind studies performed with the same criteria are necessary for an increased understanding of the effects of various antioxidants on fertility.
Abstract: In recent years, many studies have focused on the effect of oxidative stress, reactive oxygen species (ROS) and antioxidants on the male eproductive system. Under physiological conditions, sperm produces small amounts of ROS, which are needed for fertilisation, acrosome reaction and capacitation. However, if an increased production of ROS is not associated with a similar increase in scavenging systems, peroxidative damage of the sperm plasma membrane and loss of DNA integrity typically occur, which leads to cell death and reduced fertility. Furthermore, since there is no linear correlation between sperm quality and pregnancy rates, an improvement in semen parameters should not be the sole outcome considered in studies of antioxidant therapies. A definitive conclusion regarding the benefit of these therapies is difficult to obtain, as most of the previous studies lacked control groups, considered different antioxidants in different combinations and doses, or did not evaluate pregnancy rates in previously infertile couples. Even if beneficial effects were reported in a few cases of male infertility, more multicentre, double-blind studies performed with the same criteria are necessary for an increased understanding of the effects of various antioxidants on fertility.
104 citations
TL;DR: Coupling of progesterone to its receptor on the sperm plasma membrane appears to be an important step in the induction of the AR.
Abstract: The aim of the present study was to investigate whether the induction of stallion sperm acrosome reaction (AR) by progesterone is mediated by binding of progesterone to a receptor on the sperm plasma membrane or to an intracellular progesterone receptor. Progesterone-BSA conjugate labeled with fluorescein isothiocyanate (P-BSA-FITC) in combination with a vital stain, ethidium homodimer, was applied to visualize the presence of the progesterone receptor on living spermatozoa. Alternatively, an indirect immunofluorescence technique employing a monoclonal antibody (C-262) against human intracellular progesterone receptor was conducted to validate the presence of the progesterone receptor. Immunogold labeling techniques enabled ultrastructural localization of P-BSA-FITC or C-262 with transmission electron microscopy. The dynamic changes in labeling patterns were monitored for sperm cells, using fluorescence microscopy and flow cytometry during a 5-h capacitation period. An increasing number of viable cells showed affinity for P-BSA-FITC or C-262 at the acrosomal plasma membrane region of the sperm head, while a decreasing number of viable cells were not labeled. In contrast, almost all deteriorated cells were labeled in the cytosol of the postequatorial region of the sperm head. Incubation with P-BSA-FITC resulted in the induction of AR but to a lesser extent than that for sperm incubated with free progesterone. Therefore, coupling of progesterone to its receptor on the sperm plasma membrane appears to be an important step in the induction of the AR.
103 citations