Workshops

Abstract

Many important goals have been reached by reproductive biotechnologies such as sperm cryopreservation and sperm sorting. However, these procedures have often been recognized to induce changes in sperm that can affect their quality. The detrimental influence of sperm handling during reproductive biotechnologies is attributed to the dilution, and the consequent decrease in the concentration of seminal plasma, changes in temperature, buffers, osmotic stress, and mechanical forces. These stresses can induce sperm death and nonlethal modification such as membrane destabilization, which can have the features of premature capacitation. These sperm changes can alter the delicate and specific sequence of events that prepare sperm for the fertilizing event. An extensive knowledge of these handling induced changes is fundamental in order to minimize them, thus optimizing sperm survival and function. Many studies have been focused on methods effective in protecting and stabilizing sperm surface such as the use of cholesterol, antioxidants and, in particular, the exploitation of the protective effects of seminal plasma in order to improve the quality of spermatozoa subjected to reproductive biotechnologies. The workshop speakers will present an overview on the current research and the future perspective on this challenging topic.During their journey from the testis to the fertilization site, spermatozoa must undergo a series of changes in order to attain the ability to fertilize the oocyte. These changes include modifications of the sperm membrane by addition and later removal of seminal plasma (SP) proteins. Application of new sperm biotechnologies, such as sperm cryopreservation and flow cytometric sex-sorting, involve a substantial dilution or removal of SP. These procedures can alter sperm surface configuration and induce capacitation-like changes leading to a decrease in sperm fertilizing ability. Attempts to improve the outcome of these biotechnologies involve the restoration of SP to the sperm sample. The beneficial effect of SP on the spermatozoa is variable and depends upon different factors, including the source of SP, the processing of SP and the point of addition of SP to the sample. This variability can be partly overcome by the application of isolated SP proteins. In boars, most of the SP proteins belong to the sperm adhesin family. Recent studies are pointing to the PSP-I/PSP-II sperm adhesin as one of the protective factors of the SP that could be used as an additive to post-sorting collection medium. This protective effect could be related to the ability of the PSP-I/PSP-II heterodimer to hold the spermatozoa in a non-capacitated state. Further studies are needed to get a better knowledge of the effect of whole SP or its proteins in biotechnologically treated sperm functionality. (Supported by SEN-ECA (GERM 04543/07) and MINECO (AGL2012-39903), Spain.) WS 1.3 Sperm surface changes caused by assisted reproductive technologies and the influence of protective factors: how well do we speed or slow sperm readiness...