A hyaluronic acid-containing reagent compatible with glass-bottom dishes and capable of sustained binding of human spermatozoa.

Objective: Commercial products currently available for sperm selection utilizing hyaluronic acid (HA) binding prior to intracytoplasmic sperm injection (ICSI) are widely used but have some disadvantages. To potentially circumvent these limitations, we compared ICSI using a self-made hyaluronic acid (smHA) reagent with ICSI using SpermSlow.

Methods: The binding of the reagents to spermatozoa on plastic- or glass-bottom dishes was quantitated using spermatozoa that were isolated by density-gradient centrifugation and swim-up procedures (N = 10/group). Additionally, we investigated the relationship between the HA reagent used prior to ICSI and clinical outcomes after assisted reproduction with HA-ICSI (N = 81).

Results: The smHA reagent exhibited extremely stable binding to human spermatozoa. The binding time of spermatozoa was significantly longer in the smHA reagent than in SpermSlow on both plastic and glass dishes (plastic: 60.0 ± 0.0 min vs. 2.7 ± 5.9 min, P < 0.001; glass: 60.0 ± 0.0 min vs. 2.5 ± 1.8 min, P < 0.001). There were no significant differences in the normal fertilization rate between HA-ICSI with the smHA reagent (128/160, 80.0%) and HA-ICSI with SpermSlow (171/231, 74.0%, P = 0.184). The frequency of the blastocyst development from the HA-ICSI-derived zygote was significantly higher with the smHA reagent (74/101, 73.3%) than with SpermSlow (76/131, 58.0%, P = 0.019). The rates of biochemical pregnancy, clinical pregnancy, fetal heart movement, live birth, and miscarriage were not significantly different between HA-ICSI with the smHA reagent and HA-ICSI with SpermSlow.

Conclusions: The blastulation rate was higher for HA-ICSI with the smHA reagent as compared with SpermSlow. Clinical outcomes, excluding blastulation, after HA-ICSI were the same using smHA reagent and using SpermSlow. Spermatozoa binding to the smHA reagent was not attenuated over a 60-min time course. In conclusion, this reagent may shorten and simplify HA-ICSI procedures because smHA can be used with any dish material, making it easier to observe the spindle or assess intracytoplasmic morphology.