Impact of glycerol-free versus glycerol-containing fertility lubricants on sperm function, including ability to fertilize and support embryo development in an in vitro model

      OBJECTIVE: Traditional lubricants can interfere with sperm function. Fertility lubricants have been developed to not harm sperm. This study compared sperm function, including the ability to support embryo development, following contact with glycerol-free (GF) versus glycerol-containing (GC) fertility lubricants.
      DESIGN: Prospective, controlled.
      MATERIALS AND METHODS: Two experiments were done to evaluate sperm function after 30 min incubations in control media without lubricant or in treatments of media and 10% v/v lubricant including: (1) GF Pre∼Seed® (INGfertility, Spokane, WA); (2) GC ConceiveEase® (Sepal, Boston, MA); (3) GC Conceive Plus® Lot 19050; and (4) GC Conceive Plus® Lot 199X (different formulations by Sasmar, Brussels, BE). In Experiment 1, human donor sperm (n=10) were cultured in human tubal fluid medium or treatments and subjective motility evaluated. In Experiment 2, cryopreserved bull sperm were cultured in Tyrode's medium or treatments and placed with bovine oocytes (n= 40+) for IVF. Fertilization at 32 hrs and development to morulae on Day 7 were compared using Friedman's.
      RESULTS: Human sperm motility in treatments did not differ from controls (p>0.05). In the animal model, pre-fertilization exposure of sperm to all GC lubricants decreased fertilization and embryo development. The GF lubricant did not affect outcomes.
      Tabled 1Outcomes Following Sperm Exposure to Lubricants
      Treatment% Fertilization% Normal Embryos
      1102 (8)104 (18)
      292 (21)*59 (22)**
      378 (5)**49 (15)**
      473 (4)**67 (3)**
      Means (SE) as percent of control, differ at *p=0.015, **p<0.001.
      CONCLUSION: Decreased ability of sperm to fertilize and support embryo development after contact with GC lubricants suggested sublethal damage had occured. Bovine and human embryos share paternal regulation patterns, making the model valuable for detection of sublethal sperm damage impacting embryo outcomes. Maintenance of sperm function after contact with the GF lubricant supports its potential use in fertility medicine.