Spermatozoa from male mice with infertility due to Odf4 deficiency can fertilize oocytes by in vitro fertilization.

Purpose: The purpose of this study is to confirm whether in vitro fertilization (IVF) with spermatozoa from Odf4-deficient infertile males (Odf4 ^-/- spermatozoa) can lead to the development of zygotes, which was reported in a previous in vivo study.

Methods: In vitro capacitation and IVF were performed using Odf4 ^-/- spermatozoa in a small drop of TYH medium with pyruvate and glucose, for 60 min or up to 4 days. A capacitation test was performed by immunoblotting using an anti-p-Tyr antibody. A sperm movement test was performed using a computer-assisted sperm motility analysis system (SMAS). An IVF fertilization test was also performed to evaluate zygote production. Videos were taken by a DMi8 stereomicroscope equipped with a high-speed camera.

Results: In in vitro condition, Odf4 ^-/- spermatozoa with hairpin flagella harboring large cytoplasmic droplets (CDs) underwent capacitation, about 30% of large CDs were removed from spermatozoa, and the flagella became straight (capacitation test). The Odf4 ^-/- spermatozoa with straight flagella swam forward (movement test) and fertilized Odf4 ^+/+ oocytes, which eventually developed into zygotes (fertilization test).

Conclusions: By conventional IVF, spermatozoa from Odf4-deficient male mice can fertilize oocytes that then develop into zygotes. These findings can be translated to human males with infertility caused by ODF4 deficiency.