Reproduction Abstracts

The binding of sperm to the oviductal sperm reservoir appears to be an important tool to increase the population responsible for the fertilization of the oocyte cells. However, frozen sperm can lose this function due to the injuries resulting from the freezing process, therefore the aim of this study was to evaluate the binding capacity of fresh and frozen sperm to the oviduct epithelial cells (OEC), cultured in vitro. The semen from ten Andalusian stallions were used fresh and frozen using the extender Botucrio, and both semen were incubated with cells in vitro from istimo. After the incubation period, the sperm complex aggregates were transferred to a glass slide and covered with a cover slip. Two images were captured using a differential interference contrast microscope (DIC). The number of sperm bound per square millimeter of the aggregate area was calculated using an image-editing software. There was no statistical difference in the rate of the sperm to bind to the CEO using fresh and thawed semen (88.2±13.5 and 72.8±6.8 sperm/mm² of the aggregate area, respectively). This result confronts the findings of previous studies, which reported a decrease in capacity of frozen semen to bind to CEO in vitro. Probably, this occurred because the sperm frozen with Botucrio have higher structural integrity of the proteins responsible for the binding to OEC, which did not happen with other freezing diluents.

Acknowledgments: FAPESP (process: 2012/12526-4).