The Effect of Interaction NGF/p75(NTR) in Sperm Cells: A Rabbit Model

Background: Nerve Growth Factor (NGF) plays an important role in the reproductive system through its receptor's interaction (p75(NTR)). This paper aims to analyze the impact of NGF p75(NTR) in epididymal and ejaculated rabbit semen during in vitro sperm storage. Methods: Semen samples from 10 adult rabbit bucks were collected four times (n = 40) and analyzed. NGF was quantified in seminal plasma, and the basal expression of p75(NTR) in sperm was established (time 0). Moreover, we evaluated p75(NTR), the apoptotic rates, and the main sperm parameters, at times 2-4 and 6 h with or without the administration of exogenous NGF. Results: Based on the level of p75(NTR), we defined the threshold value (25.6%), and sperm were divided into High (H) and Normal (N). During sperm storage, p75(NTR) of H samples significantly modulated some relevant sperm parameters. Specifically, comparing H samples with N ones, we observed a reduction in motility and non-capacitated cell number, together with an increased percentage of dead and apoptotic cells. Notably, the N group showed a reduction in dead and apoptotic cells after NGF treatment. Conversely, the NGF administration on H sperm did not change either the percentage of dead cells or the apoptotic rate. Conclusion: The concentration of p75(NTR) on ejaculated sperm modulates many semen outcomes (motility, apoptosis, viability) through NGF interaction affecting the senescence of sperm.