Interaction between bovine spermatozoa and oviductal extracellular vesicles.

PIOTTO M; FRANCHI AN; GIOJALAS LC; DOMINGUEZ E; ADRE AJ

Congreso; Reunión Conjunta de Sociedades de Biociencias; 2017

Secretions present in the uterus and oviductal fluids affect oocyte and sperm function; however, the underlying cellular mechanisms still remain unknown. Extracellular vesicles (EV) have been recently identified along the female reproductive tract, including the uterus and oviduct, where they were called uteromes and oviductosomes, respectively. In a previous publication we showed that extracellular vesicles secreted by uterine cells stimulate human sperm capacitation, which may enhance the in vitro fertilization rate of spermatozoa. Since it is not possible to perform experiments using human gametes, the aim of this study was to establish an animal model for in vitro fertilization studies. Therefore, in order to set up a system, in this study we characterized EV obtained from bovine oviductal fluid, and analyzed their in vitro interaction with spermatozoa. We found a heterogeneous population of oviductosomes, which were ~50-500 nm in size, and presented the characteristic cup-shape morphology. After 15 minutes of in vitro co-incubation, PKH-26 labeled oviductosomes seemed to be able to fuse with spermatozoa, and according with our preliminary data, these EV also were able to stimulate sperm capacitation, as determined by induced acrosome reaction and protein tyrosine phosphorylation. Our results suggest that oviductal EV rapidly fuse with bovine spermatozoa and enhance sperm fertilizing capacity through this novel mechanism of intercellular communication.