CONICET | Buscador de Institutos y Recursos Humanos

In many mammals species the sperm association was described as a consequence of the epididymal trip. From the classic Rouleaux in Guinea pig to the most recent works in mouse and echidna, all authors had focused in a detailed morphological description of this phenomenon and the region of the epididymis where the association is detected. Other works studied this process to find a functional significance. The relationship between the sperm association and sperm cooperation/competence was proposed. But at the moment the intimate nature of this sperm interaction or the mechanism involved in this process still unclear. The aim of our work was to deepen inside the factor/s implicated in rat sperm association (Rosette). Based upon previous works that described the appearance of these Rosettes in the distal segments of the epididymis, we considered that sperm during their transit must contact with factor/s present in the caudal lumen to associate each other. We designed an in vitro sperm re associating assay consisting in co-incubate non associated sperm with several protein fractions obtained from epididymal caudal fluid, to resemble the in vivo phenomenon verified at the distal lumen. After established the most re associating fraction we characterized the proteins present by MALDI-TOF spectrometry. Among the proteins identified we found: á-1 Antitrypsin and a new protein with a á-1 Antitrypsin like domain including a sequence compatible with the Reactive Centre Loop. These proteins, members of the serine proteases inhibitors family may play a role in the process of Rosettes assembling/des-assembling modulating the luminal proteases activity.