PURPOSE Seminal pathogens can bind specifically or nonspecifically
to spermatozoa, rendering semen decontamination
procedures ineffective, whereby vertical or horizontal
transmission of the infection could occur. Serine proteases
have been demonstrated to effectively inactivate viruses and
to break pathogen-sperm bonds. However, the addition of a
protease to density gradient layers during semen processing
could negatively impact on sperm parameters. This study
investigated the effect of the addition of a recombinant,
human-sequence protease (rhProtease) on sperm parameters
during density gradient centrifugation.
METHODS (i) Pooled semen samples (n09) were split and
processed by density gradient centrifugation, with the top
density layers supplemented, or non-supplemented with
rhProtease at three different concentrations (diluted 2, 10
and 20 times). Sperm parameters were then analysed by
flow cytometry and computer-assisted semen analyses.
(ii) Semen samples (n05) were split and similarly processed
using PureSperm® Pro, with rhProtease in the 40 % density
gradient layer, or standard PureSperm® not supplemented
with rhProtease (Nidacon, International) respectively. The
Hemizona assay was then utilized to compare sperm-zona
binding post processing.
RESULTS Evaluation of sperm parameters indicated that
rhProtease did not, at any of the tested concentrations, have
an impact on (i) mitochondrial membrane potential, vitality,
motility, or (ii) zona binding potential.
CONCLUSION We report that the addition of rhProtease to density
gradients is a non-detrimental approach that could improve the
effectiveness of semen processing for the elimination of seminal
pathogens, and benefit assisted reproduction outcome.