Sperm Cell in ART (original) (raw)
Related papers
2018
Infertility today represents a global problem. Male factor contributes in approximately 50% of infertile couples. In the last decade we are witnesses of the decreased quality of semen and the increased frequency of testicular cancer and cryptorchidism. Currently, the assessment of semen quality is based on the routine semen analysis including sperm count, morphology and motility. Although variation and combination among these three main factors articulate few diagnosis, nowadays developed assisted reproduction techniques (ART), especially intracytoplasmatic sperm injection (ICSI) may be used to treat most of the male infertility problems. In general we can say that traditional semen parameters provide a limited degree of diagnostic information, thus we are aware that these indexes of diagnosis should be revisited, which includes more specific test of sperm assessments, such as DNA tests and sperm proteome.
Examinations of Sperm by Light and Electron Microscopic Levels: Friendly Preparation Techniques
Sperm examinations may be useful in both clinical and research settings, for investigating male fertility status as well as monitoring spermatogenesis during and following male fertility regulation and other interventions. Among the possible causes of male infertility, defects of sperm morphology represent an important factor that may explain decreased fertilizing potential of sperm. The limits of light microscopy can be overcome by the use of transmission electron microscopy (TEM) permits the exploration of the ultrastructural organelles rigorously which are characterizing sperm abnormalities. Electron microscopy allowed us to identify systematic sperm defects that affect the vast majority of sperm in a semen sample and non-systematic sperm defects, a heterogeneous combination of randomly distributed alterations affecting the head and the tail organelles in a varied percentage of ejaculated sperm. Correct diagnosis of specific altered sperm phenotypes is important for the advancement of new therapies. Observing a liquid material, sectioning and visualization are more difficult compared to the technically solid materials. The problems resulting from these may cause diagnostic problems. Preparation techniques we tried to display in this chapter will possibly help researchers willing to study sperm and obtain real-like visuals. 1.1 Histology of Testis Each testis is surrounded by a capsule which is called tunica albuginea. The posterior aspect of the tunica albuginea is somewhat thickened, forming the mediastinum testis, from which connective tissue septa radiate to subdivide each testis into approximately 250 pyramid-shaped as the lobuli testis. Each lobule has one to four blindly ending seminiferous tubules. Seminiferous tubule is composed of a central lumen with specialized seminiferous epithelium comprising two distinct cell populations. These cells are somatic Sertoli cells and Spermatogenic cells. Spermatozoa are produced by the seminiferous epithelium [1]. 1.2 Sperm Morphology The mature sperm consists of two components: the head and the tail. The sperm head is flattened. It is composed of the nucleus covered by the acrosome. The acrosomal cap that covers the anterior two thirds of the nucleus contains hydrolytic enzymes such as hyaluronidase, neuroaminidase and acid phosphatase. The acrosome is regarded as a special type of lysosomes. Defective sperm head shape is one of the abnormalities associated with male infertility. The sperm tail is subdivided into the neck, the middle piece, the principle piece and the end piece. The short neck contains the centrioles and the origin of the coarse fibers. The middle piece contains the mitochondria, helically wrapped around the coarse fibers and the axonemal complex. These mitochondria provide the energy for movement of the tail and thus are responsible for motility. The principal piece is the longest segment of the tail. It consists of the central axoneme surrounded by seven outer dense fibers and a fibrous sheath. The outer dense fibers provide a scaffold that contributes to the wave like movement pattern of the sperm tail. The end piece is very short segment of the tail, it contains only axonemal complex [2, 3]. 2. Fixatives for Light Microscopy
Andrology, 2018
Condensed sperm chromatin is a prerequisite for natural fertilization. Some reports suggested the prevalence of chromatin condensation defects in teratozoospermia cases with head anomalies; conversely, earlier studies exemplified its occurrence in morphologically normal spermatozoa too. The aim of this study was to compare the condensation defects in correlation with head anomalies among different groups of subfertile males and its impact on the rate of fertilization in assisted reproduction procedures. Ultrastructure analysis of spermatozoa through scanning electron microscopy and atomic force microscopy could facilitate an indepth evaluation of sperm morphology. Nuclear condensation defects (%) in spermatozoa were analyzed in 666 subjects, and its effect on the rate of fertilization was analyzed in 116 IVF and 90 intracytoplasmic sperm injection cases. There was no correlation of condensation defects with head anomalies (%). Student's t-test showed no significant changes in mean values of condensation defects in abnormal semen samples in comparison with the normal group. Condensation defects were observed in normal spermatozoa too, which was negatively associated with the rate of fertilization in IVF (p < 0.01), but intracytoplasmic sperm injection outcome remained unaffected. Ultrastructure study revealed sperm morphological features in height, amplitude, and three-dimensional views in atomic force microscopy images presenting surface topography, roughness property of head, and compact arrangement of mitochondria over axoneme with height profile at nanoscale. In pathological forms, surface roughness and nuclear thickness were marked higher than the normal spermatozoa. Thus, percentage of normal spermatozoa with condensation defects could be a predictive factor for the rate of fertilization in IVF. From diverse shapes of nucleus in AFM imaging, it could be predicted that defective nuclear shaping might be impeding the activity of some proteins/ biological motors, those regulate the proper Golgi spreading over peri-nuclear theca.
Sperm Chromatin for the Researcher, 2013
The purpose of this chapter is to provide a comprehensive overview of spermatogenesis and the various steps involved in the development of the male gamete, including cellular processes and nuclear transformations that occur during spermatogenesis, to provide a clear understanding of one of the most complex cellular metamorphosis that occurs in the human body.
Reproductive Biology and Endocrinology, 2010
Background: Although the motile sperm organelle morphology examination (MSOME) was developed only as a selection criterion, its application as a method for classifying sperm morphology may represent an improvement in evaluation of semen quality, with potential clinical repercussions. The present study aimed to evaluate individual variations in the motile sperm organelle morphology examination (MSOME) analysis after a time interval. Methods: Two semen samples were obtained from 240 men from an unselected group of couples undergoing infertility investigation and treatment. Mean time interval between the two semen evaluations was 119 +/-102 days. No clinical or surgical treatment was realized between the two observations. Spermatozoa were analyzed at greater than or equal to 8400× magnification by inverted microscope equipped with DIC/Nomarski differential interference contrast optics. At least 200 motile spermatozoa per semen sample were evaluated and percentages of normal spermatozoa and spermatozoa with large nuclear vacuoles (LNV/one or more vacuoles occupying >50% of the sperm nuclear area) were determined. A spermatozoon was classified as morphologically normal when it exhibited a normal nucleus (smooth, symmetric and oval nucleus, width 3.28 +/-0.20 μm, length 4.75 +/-0.20 μm/absence of vacuoles occupying >4% of nuclear area) as well as acrosome, post-acrosomal lamina, neck and tail, besides not presenting cytoplasm around the head. One examiner, blinded to subject identity, performed the entire study. Results: Mean percentages of morphologically normal and LNV spermatozoa were identical in the two MSOME analyses (1.6 +/-2.2% vs. 1.6 +/-2.1% P = 0.83 and 25.2 +/-19.2% vs. 26.1 +/-19.0% P = 0.31, respectively). Regression analysis between the two samples revealed significant positive correlation for morphologically normal and for LNV spermatozoa (r = 0.57 95% CI:0.47-0.65 P < 0.0001 and r = 0.50 95% CI:0.38-0.58 P < 0.0001, respectively). Conclusions: The significant positive correlation and absence of differences between two sperm samples evaluated after a time interval with respect to normal morphology and LNV spermatozoa indicated that MSOME seems reliable (at least for these two specific sperm forms) for analyzing semen. The present result supports the future use of MSOME as a routine method for semen analysis.
The nuclear status of human sperm cells
Micron, 1995
In the last decade, and in particular since the development of in vitro fertilization techniques, the nuclear status of human sperm cells has shown to be a key parameter in the assessment of male fertility. The shape and condensed state of the mature sperm nucleus are determined by structural and functional events that occur during spermiogenesis. This paper reviews essential findings on reorganization of the nucleus during sperm differentiation and maturation, and reports recent data on the architecture, biochemical composition and stability of the nucleus in human ejaculated spermatozoa. Different methods used to evaluate nuclear maturity in relation to male fertility are critically appraised.
Morphopathology of Sperm: It's Impact on Fertilization
Journal of Reproductive and Stem Cell Biotechnology, 2012
Terato-, astheno- and necrozoospermia negatively influence fertility prognosis in spontaneous conditions or with the use of various assisted reproductive techniques including conventional in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI). The correct identification of sperm pathologies will indicate different fertility potentials and outcomes in assisted reproduction technology. Anomalies of only the spermatozoa flagella bear a promising prognosis, but those affecting the sperm chromatin and the neck region entail an increasing chance of failure, which highlights the differential roles played by specific sperm components in fertilization, implantation and early embryonic development. Sperm pathology therefore allows an understanding of abnormal function that goes beyond that provided by classical sperm morphology classifications that are mainly based on descriptions of abnormal sperm shapes with no insight into the mechanisms or the pathological details.