About frogs, mice and humans

Under the direction of Dr. Silvia Arranz, Platform IBR Aquatic Biotechnology focuses primarily on developing technologies for the cultivation and conservation of fish. One of the lines of research of the laboratory is playing , where Dr. Darío Krapf worked , and studied in order to elucidate the molecular mechanisms acting during the process by which sperm acquire fertilizing capacity . The main objective is to try to export some of the results to other species of clinical interest such as human , or economic and animal production.

Not only fish

Beyond its name indicates the preference by the fish lab , there is a very important research in other models such as the history of amphibians . “We found an analogy between events related to sperm physiology in frogs and higher organisms such as human , with direct implications in the evolutionary analysis of these processes,” said Dr. Krapf . One such process is the training of the sperm.

” If you contact a human ejaculated sperm from a recent an egg , the sperm can not fertilize because it does not have the capacity to do so . This ability is acquired after ejaculation, during a period of residence in the female reproductive tract , or female in the case of other mammals. During this period , which can last from one hour in the case of the mouse until about seven hours in the case of a human , the sperm undergoes a series of physiological changes that culminate in the acquisition of fertilizing capacity ” explained Dr. Krapf .

The team involved Dario Krapf uses different vertebrate models for study , taking advantage of the benefits of each. Toads , like fish , for example , have external fertilization , which naturally means that the sperm and eggs are outside the animal body . This research group found six years ago that sperm capacitation , thought had evolved with the advent of mammals also occurs similarly in toads. In this case, factors surrounding the oocyte acting on the sperm , in preparation for fertilization. “This discovery changed the evolutionary paradigm of training,” said the researcher.

The importance of training

The understanding , at least empirically , the training enabled the realization of in vitro fertilization in humans. This required that sperm acquire fertilizing ability in the same way that would occur in the body of the female, allowing the development of assisted fertilization. This development earned him the Nobel Prize in Medicine in 2010 by biologist Robert Edwards. Regarding this issue , the problem is that there is currently unknown cross the molecular mechanisms by which sperm are trained and this is the main focus of the group that participates Dr. Krapf .

Prior to epididymal maturation process called a sperm need to be trained . “Unlike women who are born with a predetermined supply of eggs and for life , men are constantly producing sperm , which when ripe are released from the testis and fall into a tube called the epididymis. This grows to six meters long , provides an environment that is crucial for sperm maturation , but by mechanisms that are still unknown , ” Krapf said .

“There are two segments required , epididymal maturation that occurs within man and the training that occurs in the female reproductive tract. The first gives the sperm the potential to undergo training , while the second ends with a sperm capable of fertilizing an egg ” Krapf said. “We have recently published a study that realize the sperm incorporated during transit through the epididymis protein , which then participates in the training process and if this protein is not incorporated , or missing in the epididymis , it generates a infertile sperm . This work , top of the journal Developmental Biology, was the result of a collaboration of two institutes of CONICET (IBR and IBYME ) , Harvard University , and the University of Massachusetts.

The researcher explained that the importance of deepening our understanding of these processes lies in the potential of its application in both clinical and animal production and added ” Today we know that 50 % of infertility cases are caused couples in man . Of these , 20% is usually not diagnosed , referring to them as unexplained infertility . This problem is usually associated with sperm function , which is currently poorly understood. In terms of animal production , knowledge of sperm for fertilization requirements result in better production techniques. ”

“We aim to decipher what signaling pathways that are activated during training, to develop training protocols in vitro in animals in which this has not been possible, as in defective sperm that are not trained are the other hand , if are achieved inhibit some pathways may obtain an infertile sperm , which you can try a male contraception, ” said Dr. Krapf.

Good horizon

Regarding the advent of Assisted Fertilization Act , from the laboratory submits that represents a drive to try to achieve that new advances in assisted reproduction but low complexity with good results , which will be treatments that somehow assume that will promote social work . “Our efforts are meeting to try to get a sperm can fertilize on their own , and the way is trying to circumvent some way defective or not working properly , trying to get them back to the capacitated sperm to the female body through assisted insemination. That would be the most ideal ” concluded the researcher .