Seminal extracellular vesicles influence porcine spermatozoa physiology by modulating key functional parameters

Area of Science:

• Reproductive Biology
• Extracellular Vesicles Research
• Sperm Physiology

Background:

• Seminal plasma (SP) contains extracellular vesicles (EVs) that modulate sperm function.
• The specific roles of different seminal EV (sEV) subsets are not well understood.
• Investigating sEV interactions with spermatozoa is crucial for understanding reproductive processes.

Purpose of the Study:

• To evaluate the interaction of small (S-sEVs) and large (L-sEVs) subsets with pig spermatozoa.
• To determine the effects of these sEV subsets on sperm function under varying pH conditions.
• To elucidate the impact of sEVs on oxidative stress, mitochondrial potential, and apoptosis in spermatozoa.

Main Methods:

• Isolation and characterization of sEV subsets from seminal plasma using size exclusion chromatography.
• Incubation of porcine semen with sEV subsets under different pH conditions (6.5, 7.0, 7.5).
• Assessment of sperm functional parameters including reactive oxygen species, mitochondrial membrane potential, and apoptosis via flow cytometry and confocal microscopy.

Main Results:

• Both S-sEVs and L-sEVs readily bound to and were internalized by spermatozoa, irrespective of pH.
• sEVs significantly reduced reactive oxygen species production and mitochondrial activity.
• sEVs increased apoptosis in viable spermatozoa, with effects on acrosome integrity being time- and condition-dependent.

Conclusions:

• Small and large seminal EVs interact with porcine spermatozoa across physiological pH ranges.
• This interaction leads to reduced oxidative stress and mitochondrial activity in sperm.
• The study highlights the complex role of sEVs in modulating sperm viability and function, including increased apoptosis.