Sperm Membrane Channels Receptors And Kinematics Using Boar Spermatozoa For Drug Toxicity Screening

Internal fertilization usually implies that a spermatozoon, with intact attributes for zygote formation, passes all hurdles during its transport through the female genitalia and reaches the oocyte. During this journey, millions to billions of other spermatozoa perish. Spermatozoa are highly differentiated motile cells without synthetic capabilities. They generate energy via glycolysis and oxidative phosphorylation to sustain motility and to maintain the stability and functionality of their plasma membrane. In vivo, they spend their short lifespan bathing in female genital tract fluids of different origins, or are in vitro exposed to defined media during diverse sperm handling i.e. extension, cryopreservation, in vitro fertilization, etc. Being excitable cells, spermatozoa respond in vivo to various stimuli during pre-fertilization (capacitation, hyperactivation, oocyte location) and fertilization (acrosome reaction, interaction with the oocyte) events, mediated via diverse membrane ion-conducting channels and ligand-gated receptors. The present Thesis has mapped the presence and reactivity (sperm intactness and kinematics) of selected receptors, water and ion channels in ejaculated boar spermatozoa. The final aim was to find a relevant alternative cell type for in vitro bioassays that could ease the early scrutiny of candidate drugs as well as decreasing our needs for experimental animals according to the 3R principles. Spermatozoa are often extended, cooled and thawed to warrant their availability as fertile gametes for breeding or in vitro testing. Such manipulations stress the cells via osmotic variations and hence spermatozoa need to maintain membrane intactness by controlling the exchange of water and the common cryoprotectant glycerol, via aquaporins (AQPs). Both AQPs-7 and -9 were studied for membrane domain changes in cauda- and ejaculated spermatozoa (un-processed, extended, chilled or frozen-thawed). While AQP-9 maintained location through source and handling, thawing of ejaculated spermatozoa clearly relocated the labelling of AQP-7, thus appearing as a relevant marker for non-empirical studies of sperm cryopreservation. Alongside water, spermatozoa interact with calcium (Ca2+) via the main Ca2+ sperm channel CatSper. Increments in intracellular Ca2+ initiate motility hyperactivation and the acrosome reaction. The four subunits of the CatSper channel were present in boar spermatozoa, mediating changes in sperm motility under in vitro capacitation-inducing conditions (increased extracellular Ca2+ availability and bicarbonate) or challenge by the CatSper antagonists mibefradil and NNC 55-0396. Uterine and oviduct fluids are richest in endogenous opioids as ?-endorphins during mating and ovulation. Both ?- and ?- opioid receptors were present in boar spermatozoa modulating sperm motility, as in vitro challenge with known agonists (?: morphine; ?: DPDPE and ?: U 50488) and antagonists (?: naloxone; ?: naltrindole and ?: nor-binaltrorphimine) showed that the ?-opioid receptor maintained or increased motility while the ?-opioid receptor mediated decreased motility over time. Finally, boar spermatozoa depicted dose-response effects on sperm kinematics and mitochondrial potential following in vitro challenge with 130 pharmacological drugs and toxic compounds as well as with eight known mito-toxic compounds. In conclusion, boar spermatozoa expressing functional water (AQPs-7 and -9) and ion (CatSper 1-4) channels as well as ?- and ?-opioid receptors are able to adapt to stressful environmental variations, capacitation and pharmacological compounds and drug components. Ejaculated sperm suspensions are easily and painlessly obtained from breeding boars, and are suitable biosensors for in vitro drug-induced testing, complying with the 3R principles of reduction and replacement of experimental animals, during early toxicology screening.

Deficiencies in sperm function are usually the result of spermatogenic defects. Spermatogenesis is a biologically complex and essential process during which spermatogonia undergo meiotic recombination, reduction of the genome to a haploid state, and extensive cellular modifications that result in a motile cell capable of traversing the female reproductive tract, withstanding various potential assaults to viability, and finally successfully fertilizing a mature oocyte to give rise to an embryo. Defects in any step of spermatogenesis or spermatogenesis can lead to male infertility, a disease that affects approximately 5-7% of the population. Spermiogenesis and Spermatogenesis: Methods and Protocols details protocols used in the study of spermatogenesis, clinical analytical protocols, and basic techniques used in clinical andrology laboratories, such as obtaining accurate results for a sperm count, and advanced procedures, such as genome-wide genetic study tools and evaluation of nuclear proteins. Written in the successful Methods in Molecular BiologyTM series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible protocols, and notes on troubleshooting and avoiding known pitfalls. Authoritative and easily accessible, Spermiogenesis and Spermatogenesis: Methods and Protocols is unique in its breadth, and will be a useful reference for clinicians and researchers alike.

In vitro fertilization has resulted in an estimated 4000-5000 births in the world. The procedure has been accepted in Europe, America and Australia and several hundred IVF clinics are operating successfully. The newer procedures of GIFf, embryo freezing and donor oocyte IVF have become established and are dealt with in several chapters. GIFf has become the procedure of choice for patients with infertility of unknown origin. Oocyte freezing represents an important new technology which is being developed. The routine IVF procedure has improved slightly; variation in results can be reduced by quality control of laboratory and clinical techniques. Male factor infertility has been dealt with by IVF in mild and moderate cases, but newer techniques will be required to deal with severe problems in the male. Most countries have accepted that the straightforward IVF pro cedure is ethical. Limitations concerning the use of donor oocytes and embryo experimentation exist in some religions and countries; legal control of the new reproductive technologies ranges from the passage of statutes to no control at all. Many countries are still considering the need for legislative control. The text endeavours to indicate new areas of importance and to guide those organizing services as to how to introduce newer technolo gies.

Oxidants, Antioxidants and Impact of the Oxidative Status in Male Reproduction is an essential reference for fertility practitioners and research and laboratory professionals interested in learning about the role of reactive oxygen species in sperm physiology and pathology. The book focuses on unravelling the pathophysiology of oxidative stress mediated male infertility, recruiting top researchers and clinicians to contribute chapters. This collection of expertise delves into the physico-chemical aspects of oxidative stress, including a new focus on reductive stress. Furthermore, the inclusion of clinical techniques to determine oxidative stress and the OMICS of reductive oxidative stress are also included. This is a must-have reference in the area of oxidative stress and male reproductive function. Offers comprehensive information on oxidative stress and its role in male reproduction, including new therapeutic approaches Deals with current approaches to oxidative stress using OMICS platform“/li> Designed for fertility practitioners, reproductive researchers, and laboratory professionals interested in learning about the role of reactive oxygen species in sperm physiology and pathology

Papers presented at the VII International Congress of Reproductive Immunology held from 27-30 October 1998, New Delhi ; organised by National Institute of Immunology.

The decade that has passed since publication of the second edition of this textbook has not only witnessed a tremendous increase in knowledge within the ? eld of and- logy, but also seen the ? eld itself achieve a newfound status within the medical p- fession. Knowledge and status have been of mutual bene? t to the ? eld and the growing critical mass of diagnostic and therapeutic possibilities have caused andrology to be recognized as a medical subspecialty in some countries such as Germany, Poland, and Estonia. The European Academy of Andrology (EAA) served as a pacemaker for this development and continues to strive for establishment of andrology as a clinical ? eld. Well-designed curricula and qualifying examinations have contributed to the of? cial recognition of andrology as a speciality. This recognition of the ? eld helps patients with andrological problems to ? nd the specialist they seek. This textbook summarizes the current state of knowledge in the ? eld of andrology. It is a source of knowledge to all those who are or want to become andrologists. In addition, as andrology is clearly an interdisciplinary ? eld, this book may serve as a compendium and source of reference for all those physicians and biologists active in neighboring areas, who want to obtain an overview of andrology and who require information on special problems. The extensive references are timely and up to date.

This unique book deals almost wholly with the clinical aspects of the subject. Male Infertility is a book written by a clinician for clinicians, most frequently gynaecologists who are battling to understand reproductive pathology in the infertile male patient. It is intended to familiarize the gynaecologist and other interested clinicians in the clinical management of an infertile man and provide that individual with practical guidance to a clinical problem.