Espermatozoides, complexos cúmulo-oóforo e embriões bovinos em estágio inicial possuem a capacidade intrínseca de ligar e internalizar microRNAs?

Abstract

MicroRNAs (miRNAs) are a small class of non-coding RNAs that regulate gene expression post-transcriptionally and play a significant role in reproductive processes, including early embryonic development. Beyond their intracellular activity, these molecules are found in biological fluids and various reproductive tract tissues—often associated with extracellular vesicles—highlighting their capacity for transport and involvement in cell-to-cell communication. This study aimed to evaluate, in vitro, the intrinsic capacity of bovine spermatozoa, cumulus oocyte complexes (COCs), and early-stage embryos to internalize miRNA molecules. To this end, Alexa Fluor 488-labeled Scrambled siRNA was added to the maturation, Talp-sperm, and embryo culture media. Following incubation, samples were analyzed via confocal microscopy to assess molecule internalization. Spermatozoa and embryonic cells displaying small fluorescent signals within them were observed; however, this was not seen in the COCs. These results demonstrate that spermatozoa and early-stage embryos possess the ability to internalize miRNAs present in the Talp-sperm and in vitro culture (IVC) media, respectively. It is important to note that these findings require confirmation through molecular biology experiments.