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

Abstract 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.