1,721,234 research outputs found
Three cases of genetic defects affecting sperm tail: a FISH study
No full textSubmicroscopic alterations in the cytoskeletal structure of sperm flagellum are associated with severely reduced or completely absent motility in subfertile or infertile men. Sometimes these alterations can be related to well known genotypic defects when the same anomaly affects the whole sperm population. Transmission electron microscopy (TEM) is the only tool able to specifically characterize the morphological features of genetic sperm defects. In this study, the frequencies of aneuploid and diploid spermatozoa were identified in three patients showing specific flagellar anomalies, each of them affecting the whole sperm population: dysplasia of the fibrous sheath, primary ciliary dyskinesia and absence of fibrous sheath. All these defects were highlighted by TEM. Fluorescence in situ hybridization (FISH) analysis was performed on decondensed sperm nuclei for chromosomes 18, X and Y, highlighting higher diploidies and sex chromosome disomies in cases of dysplasia of the fibrous sheath and primary ciliary dyskinesia, in agreement with other reports. We have also described FISH results in spermatozoa with absence of fibrous sheath. In this case, the only one reported due to the rarity of this defect, the aneuploidies and diploidies were within normal range. These data contribute to the growing evidence that genetic sperm defects of sperm flagella are generally correlated with meiotic segregation derangement. For this reason, genetic counseling is advisable, although all the genes involved and the possible mechanisms of these mutations have not yet been fully characterize
Role of isoprostanes in human male infertility
No full textOne of the major causes of defective sperm function is oxidative stress, which limits the fertilizing potential of these cells as the result of collateral damage to proteins and lipids in the sperm plasma membrane. On this point, a derangement of both generation and neutralization of reactive oxygen species (ROS) is a recognized cause of male infertility. Antioxidant protection in sperm has been widely investigated, as well as the sperm composition of fatty acids (FA), which represents the preferred substrate for ROS, most frequently linked to the disease-related infertility. Isoprostanes are compounds derived from free radical-mediated oxidation of FAs. As such, they are considered an index of lipid oxidative damage and lipid mediators. This article discusses the role of isoprostanes as relevant factors both to sperm FA composition and sperm membrane integrity. Additionally, isoprostane’s influence on sperm quality is reviewed. With reference to male reproductive dysfunction, increasing evidence indicates isoprostanes, detectable in biological fluids or sperm membrane, as the specific index of 1) exposure to chemical etiological agents, 2) oxidative damage, 3) reduced antioxidant response, and 4) sperm immaturity. Abbreviations: OS: oxidative stress; ROS: reactive oxygen species; PUFAs: polyunsaturated fatty acids; ARA: arachidonic acid, F2-IsoPs; F2-isoprostanes, PLA2: phospholipase A2; NADPH: nicotinamide adenine dinucleotide phosphate; IVF: in vitro fertilization
Study of cytoskeleton from microscopic point of view: Our experience
Full text linkThe manuscript deals with our studies and experiences in the assessment of cytoskeleton in different cellular models and situations. The immunofluorescent study of several cytoskeletal proteins was relevant in the evaluation of a therapy for osteoarthritis, in case of alkaptonuria and in testing the efficacy of docetaxel in neuroblastoma cancer cells leading to apoptosis. A relevant part of our experience focus on the study of cytoskeleton in seminiferous epithelium and spermatozoa, identifying alterations affecting blood-Testis barrier after a silver nanoparticle treatment, chromosomal segregation in case of varicocele, sperm motility and diagnosing systematic sperm defects as "Primary ciliary dyskinesia" and "Dysplasia of the fibrous sheath". The evaluation of cytoskeleton represents a specific and sensitive analysis in establishing the health status of different cells
Spermatozoa and chronic treatment with finasteride: a TEM and FISH study
No full textFinasteride is a specific inhibitor of the 5alpha reductase enzyme originally approved for the treatment of benign prostatic hypertrophy and also for the treatment of androgenetic alopecia (AGA) in men at a dose of 1 mg/day. We report on three cases of young men recruited at our Centre for Male Infertility who had used finasteride for five years. Semen quality was investigated by light microscopy to evaluate sperm concentration and motility. Sperm morphology was performed by transmission electron microscope (TEM) and the data were analyzed. The presence of Y microdeletions was investigated by PCR. Meiotic segregation was explored by fluorescence in situ hybridization (FISH). Patient 1 was azoospermic, patients 2 and 3 showed a normal sperm concentration and severely reduced progressive motility. TEM analysis revealed altered sperm morphology consistent with necrosis and FISH data revealed elevated diploidy and sex chromosome disomy frequencies. This examination was repeated 1 year after the men had suspended the use of finasteride, without receiving any other treatment. A recovery of spermatogenetic process was observed. Motility and morphology improved whereas the meiotic pattern did not change presenting elevated diploidy and sex chromosome disomy frequency
Morphology and meiotic segregation in spermatozoa from men of proven fertility
No full textEstimates of semen parameters are important for defining normal ranges, which are currently established by 1999 World Health Organization guidelines. However, it is well known that semen evaluation is questionable because it is necessary for only 1 sperm to be able to reach and fertilize the oocyte. Spermiogram parameters and sperm morphology, evaluated by transmission electron microscopy (TEM), were performed on semen samples from 25 men of proven fertility. Despite a generally normal sperm concentration, progressive motility was reduced in 9 cases. Sperm characteristics were evaluated with an established technique, and the mean of the percentages of sperm pathologies were confirmed by comparing to previous reports. A comparison of apoptosis and necrosis in the samples, as detected by TEM and an annexin V/propidium iodide assay, was also performed. Fluorescence in situ hybridization was carried out on the same samples using probes for chromosomes 18, X, and Y. The mean value of the frequency of total aneuploidy in the analyzed group was 0.627% (25th percentile = 0.563%; median = 0.625%; 75th percentile = 0.690%). This study of the incidence of disomy and diploidy in spermatozoa from fertile, apparently normal individuals is important for making comparisons with infertile cohorts to determine the real increase of aneuploidy in those cohorts
Promiscuous coupling and involvement of protein kinase C and extracellular signal-regulated kinase 1/2 in the adenosine A1 receptor signalling in mammalian spermatozoa
No full textMammalian spermatozoa require a maturational event after ejaculation that allows them to acquire the capacity for fertilisation. This process occurs spontaneously during the transit through the female reproductive tract where spermatozoa are in contact with micromolar concentrations of adenosine that might act as a capacitative effector. This study shows that the adenosine A1 receptor agonist, 2-chloro-N6-cyclopentyladenosine, can induce capacitation, i.e., the ability to undergo the acrosome reaction and to become fertile. This receptor, already known to be bound to Galpha(i2), is also bound to G(q/11). These G proteins are functional in the signalling pathway elicited by the A1 receptor and correlate with the multiple intracellular events that follow its activation. The use of protein kinase C isoform inhibitors and MEK inhibitors, resulting in the abolition of the biological response to the selective agonist, indicates the involvement of protein kinase C and MEK in its signalling. In agonist-treated spermatozoa an extracellular calcium influx, involvement of alpha and gamma PKC isoforms and transient phosphorylation of ERK1/2 have been observed. Our results, besides showing that adenosine A1 receptor prompts mammalian spermatozoa to undergo the acrosome reaction hence supporting a role for adenosine as agent for fertilisation, show that 2-chloro-N6-cyclopentyladenosine triggers signalling mechanisms that involve both Galpha(i2) and G(q/11), extracellular calcium influx, modulation of classical Ca2+-dependent PCK isoforms and up-regulation of the ERK1/2 phosphorylation
Relevance of Fatty Acids to Sperm Maturation and Quality
Full text linkAlmost 50% of infertility cases are associated with human male infertility. The sperm membrane is a key structure influencing sperm morphology and function in normal and pathological conditions. The fatty acid profile determines the performance not only of sperm motility but also of acrosomal reaction and sperm-oocyte fusion. This review presents available knowledge on the role of fatty acid composition in human sperm and spermatogenesis and discusses the influence of dietary fatty acids on the sperm fatty acid profile. Recent studies in biological sciences and clinical researches in this field are also reported. The topic object of this review has potential application in medicine by identifying potential causes of infertility
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