β-NGF and its receptors are present in ram sperm cells, but β-NGF was undetectable in seminal plasma

Context In males, the nerve growth factor β (β-NGF), along with its receptors TrkA and p75, is closely related to semen traits and quality in certain species. However, to the best of our knowledge, no study has addressed either the existence of this neurotrophin and its receptors on ram sperm cells or the relationship between β-NGF and semen traits. Aims The aim of this study was to determine the expression of β-NGF and its receptors in spermatozoa and to relate the concentration of β-NGF in seminal plasma to sperm morphology and quality in rams. Methods The expression of β-NGF and its receptors in sperm cells was performed using immunofluorescence, and the concentration of β-NGF in semen was determined by enzyme-linked immunosorbent assay. Key results β-NGF, TrkA and p75 were detected in the spermatozoa of the ram; however, β-NGF was not detectable in the seminal plasma. Conclusions This study provides evidence, for the first time, of the presence of β-NGF and its receptors TrkA and p75, in spermatozoa of rams. However, it was undetectable in seminal plasma collected during the transition from the breeding to the non-breeding season. Detecting and quantifying β-NGF in ram seminal plasma presents several challenges, primarily due to its low concentrations and the techniques employed. Implications These findings indicate that rams, among the males, have β-NGF and its receptors present in sperm cells, making them another candidate species to expand our knowledge of this important protein in mammalian reproduction.