Effect of platelet rich plasma lysate and fibroblast growth factor 2 on stallion sperm motility

Abstract

Growth factors (GFs) are known to modulate cell function and their presence in semen could be advantageous to sperm. In humans and
mice, fibroblast growth factor 2 (FGF2) improved semen motility. Platelet rich plasma (PRP), rich in GFs including FGF2, reduced post
mating inflammatory response within the uterus; however, its effects on sperm are not known. PRP lysate (PRPL) is much purer than PRP
and contains higher concentrations of GFs. Hence, the objective of the present study was to evaluate the effect of supplementing fresh
and cool-stored stallion sperm with either PRPL at 1, 2.5, 5, and 10% (also containing 1 IU/ml of heparin), or FGF2 at 0.1, 1, 10, and
100 ng/ml. Motility parameters were evaluated using computer assisted semen analysis at 0, 0.5, 1, 1.5, 6, and 24 hours after treatment.
For both PRPL and FGF2 treatments, there were no differences in total and progressive motility among groups. Concentrations of PRPL
> 5% induced sperm agglutination via head-to-head attachment, starting at hour 1 and was more pronounced for 10% PRPL than 5%
PRPL, suggesting a dose-dependent characteristic. Direct addition of PRPL to semen extender at doses < 5% might not substantially
affect sperm motility, whereas doses > 5% might affect sperm motility due to head-to-head attachments. Addition of FGF2 at the
concentrations studied may not affect sperm characteristics.