Lactobacillus plantarumsecretions may exert a cryoprotective effect on human sperm motility: A prospective in vitro study

Abstract

AbstractBackgroundSemen cryopreservation is a widely used procedure for fertility preservation, despite some level of cryodamage that may occur in spermatozoa after thawing. However, there is some evidence that lactobacilli, one of the bacteria found in semen, might benefit sperm quality.ObjectivesThis study aims to determine whether the addition ofLactobacillus plantarumsecretions to sperm freezing medium has an impact on sperm motility, morphology, and DNA fragmentation.Materials and methodsThis is a prospective auto‐controlled study. It was conducted on 30 raw semen samples from 30 infertile men attending a fertility center for semen analysis. Before freezing, all the samples were analyzed for motility, morphology, and DNA fragmentation percentages. Each sample was then divided equally into three aliquots. Cryopreservation was performed on each aliquot using one of the following three media: withoutLactobacillus plantarumsecretions (control group) or with 107or 108colony‐forming units/mLLactobacillus plantarumsecretions. Sperm motility, morphology, and DNA integrity were evaluated after the cryopreservation media were added and after semen thawing.ResultsThe results of this study indicated that after thawing, no statistically significant decrease in progressive motility and non‐progressive percentages were detected in the sperm freezing medium supplemented with 108colony‐forming units/mLLactobacillus plantarumsecretions than the fresh raw semen. Moreover, multivariate linear regression model analyses showed that the progressive motility (p = 0.02), non‐progressive motility (p = 0.016), and non‐motile spermatozoa (p = 0.012) percentages were significantly decreased in the freezing medium (withoutLactobacillus plantarumsecretions) compared to the fresh raw semen.Discussion and conclusionTo the best of our knowledge, this is the first study showing thatLactobacillus plantarumsecretions had a cryoprotective effect on sperm motility when added to the sperm freezing medium. Furthermore,Lactobacillus plantarumsecretions were found to protect sperm DNA integrity more effectively than the freezing medium withoutLactobacillus plantarumsecretions in non‐normozoospermia group. Cryopreservation procedures must therefore be optimized to minimize any iatrogenically induced sperm DNA damage, given the correlation between sperm DNA damage and increased mutation loads in progeny.