Cytoskeletons (F-actin) and spermatogenesis
C. Yan Cheng in Spermatogenesis, 2018
Spermatozoa are produced during the complex and elegant process of spermatogenesis. These specialized cells arise from immature diploid spermatogonia, which undergo meiosis to produce haploid gametes. The sperm structure develops during spermiogenesis, where a round haploid germ cell (round spermatid) is transformed into a spermatozoon by the development of a motile cilium, a streamlined nucleus, and an acrosomal cap required for fertilization. All aspects of male germ cell development are supported by the somatic Sertoli cell; this large and structural complex cell simultaneously supports multiple germ cells at different phases of development, providing both the structural and nutritional support required to execute the spermatogenic program. Spermatogenesis is highly dynamic and precisely controlled in space and time and is accompanied by extraordinary changes in each cell’s cytoskeleton. This chapter will address the role of a particular cytoskeletal component, actin, in spermatogenesis.
The Use of Sperm Ultra-Morphology Assessment in Assisted Reproduction
Nicolás Garrido, Rocio Rivera in A Practical Guide to Sperm Analysis, 2017
In 2002, Bartoov et al.10 introduced a light imaging system called motile sperm organelle morphology examination (MSOME) that observes spermatozoa in real time and at a high magnification. They used an inverted microscope equipped with Nomarski differential interferential contrast microscopy and a ×100 immersion objective. This microscope is also equipped with a 3D camera and a color monitor. The final magnification that takes into account the microscope lens and the zoom of the video monitor is close to ×6600. It allows the analysis in real time of isolated motile spermatozoa placed into a petri dish with glass bottom at high magnification (up to ×6600). The different parts of the spermatozoon such as the acrosome, the postacrosome, the neck, the middle piece, the flagellum, and the nucleus are described. A normal spermatozoon has an oval head, which is smooth and symmetrical; its size varies between 4.75 ± 0.28 μm in length and 3.28 ± 0.2 μm in width. These criteria were defined arbitrarily using the previous examination of TEM studies. Chromatin is considered abnormal if more than one vacuole occupies more than 4% of the total sperm head surface. A normal head should have a normal shape and a normal content.10,15,16 MSOME is able to identify not only solely conventional morphological sperm alterations with a definition close to SEM but also more specifically sperm head vacuoles, considered by Bartoov et al. (2001)16 to be nuclear defects. The specific sperm morphological abnormalities found in MSOME are summarized in Table 11.1.
Preparation and evaluation of oocytes for intracytoplasmic sperm injection
David K. Gardner, Ariel Weissman, Colin M. Howles, Zeev Shoham in Textbook of Assisted Reproductive Techniques, 2017
The egg released from the ovarian follicle is accompanied by the cumulus cells. Prior to ovulation, in concomitance with oocyte maturation, the cumulus undergoes characteristic transformations that are also stimulated by LH. In response to this gonadotropin, the cumulus cells produce specific glycosaminoglycans, the secretion of which results in cumulus mucification and its expansion. The major component of the extracellular matrix secreted by the cumulus cells is hyaluronic acid (3–7). The mucified cumulus mass that encapsulates the ovulated egg is penetrated by the spermatozoon that uses enzymes localized on its surface membrane to accomplish this mission. Sperm membrane protein PH-20, which is present on the plasma membrane of sperm cells of many species, such as guinea pigs, mice, macaques, and humans, exhibits hyaluronidase-like activity that facilitates this action (8–11). Furthermore, a later study has demonstrated that a plasma membrane-associated hyaluronidase is localized to the posterior acrosomal region of equine sperm (12).
Systematic review of antioxidant types and doses in male infertility: Benefits on semen parameters, advanced sperm function, assisted reproduction and live-birth rate
Published in Arab Journal of Urology, 2018
Basic semen analysis has been criticised for being a poor predictor of fecundity. Whilst it provides useful information on the patency of sperm production, secretions of the accessory organs, as well as ejaculation and emission, it does not predict fertility [78,79]. It provides no insights into the functional potential of the spermatozoon to fertilise an ovum or to undergo the subsequent maturation processes required to achieve fertilisation. As such, advanced tests of sperm function were developed to provide a better understanding of the true contribution of the human sperm to conception aiming to improve the predictive power of semen studies in this regard. Of the different advanced sperm function tests that have been developed, SDF and measures of OS have been most commonly investigated.
Artificial oocyte activation with calcium ionophore for frozen sperm cycles
Published in Systems Biology in Reproductive Medicine, 2018
Seda Karabulut, Özlem Aksünger, Can Ata, Yusuf Sağıroglu, İlknur Keskin
2006; Moaz et al. 2006; Nasr Esfahani et al. 2007). The mean fertilization rate after microinjection is known to be 70–80%, which depends on the quality of the gametes and culture conditions (Palermo et al. 2009; Neri et al. 2014). Fertilization failure after ICSI is suggested to be the result of an oocyte activation deficiency (Neri et al. 2014; Swain and Pool 2008; Yanagida 2004; Rawe et al. 2000). A successful oocyte activation depends on the factors related both to the sperm and oocyte, and is mediated by oscillations in Ca2+ concentration in the cytoplasm of the oocyte. It is triggered by the sperm factor phospholipase C zeta (Saunders et al. 2002; Tesarik et al. 2002; Kashir et al. 2010, 2015; Amdani et al. 2013). Ca2+ signaling and Ca2+ release from intracellular stores are crucial for oocyte activation and further embryonic development (Kline and Kline 1992; Ozil and Huneau 2001; Marangos and Carroll 2004; Ducibella et al. 2006). Oocyte activating ability of the spermatozoon is a critical factor for fertilization. During natural fertilization, oocyte activation is achieved by the entrance of the sperm leaving its membrane outside the oocyte. Ooplasmic factors can thereby interact with the sperm nucleus. However, during ICSI, the sperm cell is introduced into the ooplasm as a whole. Fertilization problems are suggested to appear as a result of the impairment in the release of oocyte activating factors from the sperm following ICSI (Nasr Esfahani et al. 2007).
The use of platelet-rich plasma (PRP) to improve structural impairment of rat testis induced by busulfan
Published in Platelets, 2019
Farzaneh Dehghani, Narges Sotoude, Hossein Bordbar, M.R. Panjeshahin, Saied Karbalay-Doust
The spermatozoon samples were prepared for sperm flagella length assessment. A × 60 oil immersion objective with a numerical aperture of 1.4 was used to visualize the tail better. The length was estimated according to the same stereological methods estimating the length in two-dimensional space. The microscopic fields were sampled according to the rules for systematic random sampling. Briefly, the microscope stage was moved in an equal interval along the X- and Y-direction of the microscope stage, using the stage micrometer of the microscope. About 100–150 spermatozoa were sampled on each slide. To achieve an acceptable precision, it has been advised that at least five specimens in each group should be analyzed, and 100–200 probe interaction (e.g., sampling of 100–200 spermatozoon heads by counting frame, or 100–200 intersections of Merz grid with spermatozoon tails) should be considered. In each sampled microscopic field, a test system including two elements was superposed on the image of the monitor. The first component was the unbiased counting frame. In this frame, if a spermatozoon’s head lay inside the frame and did not touch the forbidden lines (left and inferior borders of the frame), it was sampled. Merz grid is a curve consisting of two equal semicircles (21). The following formula was used to estimate the mean spermatozoon tail length: