P-078 In vitro effects of polycarbophil vaginal moisturizing gel on sperm motility and vitality

Abstract

Abstract Study question The aim of this study was to evaluate the possible effects of intravaginal polycarbophil gel in sperm quality in an in vitro model. Summary answer Incubation of human sperm samples with a vaginal moisturizer containing polycarbophil gel 10% resulted in important reduction of sperm motility and vitality. What is known already The possible effect of lubricants on sperm quality has been a matter of debate for over 50 years. Despite the publication of a few studies, the real impact of lubricants on male gametes is remains unknown. Some commercial lubricants have been tested but so far there is a lack of studies evaluating the impact of vaginal moisturizers on seminal quality. Vaginal dryness is a recurring and significant complaint affecting couples trying to conceive who may use lubricants, vaginal moisturizers or even natural oils that could advsersely interfere with seminal quality. Study design, size, duration This paired prospective study involved seminal samples obtained fom 14 men undergoing fertility treatment at a private IVF clinic in Brazil from August/2020 to July/2022. The study was approved by the local review board and each participant signed an informed consent. Each sample was divided into two aliquots: 20% polycarbophil gel (final dilution 10%) or medium only. Statistical analysis was performed using D’Agostino/ Pearson, General Linear Model, Wilcoxon, Friedman’s. P values <0.05 were considered significant. Participants/materials, setting, methods Normozoospermic samples of 14 patients (alpha 0.05, power 0.8)were collected by masturbation, 2 to 5 days after the last ejaculation. After liquefaction ,10 μmL were analyzed using a Makler chamber according to World Helath Organization (WHO) guidelines. Samples were mixed 1:1 v/v with 20% policarbophil gel or with culture medium only, then incubated for 24h at 34 °c. Analysis were performed at 0, 15, 30 min and 24h to determine progressive motility and vitality (eosin-nigrosin test) Main results and the role of chance There was a significant decrease of sperm motility according to the WHO classification in both experimental conditions over time, but the reduction was more evident in the samples treated with polycarbophil gel (p < 0.0001 group x time, General LinearModel for Repeated Measure). The proportion of progressively motile sperm reduced immediately upon contact of the seminal sample with polycarbophil gel (time point 0 min) and decreased throughout the experiment, contrasting to incubation with culture medium (control), which only affected substantially sperm motility after 24h. In the validation cohort, the proportion of progressively motile sperm decreased from a median of 52% in fresh samples to 11% after 24h incubation with culture medium and 0% after 24h incubation with polycarbophil gel (p < 0.0001). Sperm vitality at the end of the experiment also differed significantly between treatments, with medians of 62.5% after exposure to culture medium and 47% after exposure to polycarbophil gel (p = 0.020, Wilcoxon’s test) Limitations, reasons for caution Results represent samples from a selected group of men undergoing fertility treatment at a private center in Brazil. The effect of polycarbophil gel in fertile males may be different. Moreover, the in vitro setting used here does not accurately mimic the vaginal environment which could interfere with the results. Wider implications of the findings Polycarbophil-based gels and similar products may harm sperm vitality and motility, therefore woment trying to conceive should avoid the use of such products until more studies prove otherwise. Trial registration number Not applicable