title: Mitochondrial hydrogen peroxide and defective cholesterol efflux prevent in vitro fertilization by cryopreserved inbred mouse sperm.
abstract: Recent advances in the cryopreservation of mouse sperm have resulted in dramatically improved in vitro fertilization (IVF) rates, but the biological mechanisms underlying the techniques remain unclear. Two different classes of compounds have been widely utilized to improve the IVF rates of cryopreserved mouse sperm: antioxidants and cyclodextrins. To determine how cryopreservation reduces mouse sperm IVF and how antioxidants and cyclodextrins mitigate this effect, we examined sperm function and oxidative damage after cryopreservation, with and without treatments, in mouse strains important for biomedical research. Our investigation revealed mouse strain-specific effects on IVF by modulation of oxidative stress and cholesterol efflux of cryopreserved sperm. Antioxidants improved IVF rates of C57Bl6/J cryopreserved mouse sperm by reducing hydrogen peroxide produced by sperm mitochondria and ameliorating peroxidative damage to the sperm acrosome. Enhancing cholesterol efflux with cyclodextrin restored capacitation-dependent sperm function and IVF after cryopreservation of C57Bl/6J, C57Bl/6N, and 129X1 mouse sperm. Our results highlight two accessible pathways for continued development of IVF techniques for mouse sperm and provide novel endpoints prognostic of IVF success. These insights may improve sperm cryopreservation methods of other mouse strains and species.
authors.affiliation: Department of Genetics, the Carolina Center for Genome Sciences, and the Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC, USA.
authors.forename: Jeffrey E
authors.initials: JE
authors.lastname: Gray
authors.forename: Joshua
authors.initials: J
authors.lastname: Starmer
authors.forename: Vivian S
authors.initials: VS
authors.lastname: Lin
authors.forename: Bryan C
authors.initials: BC
authors.lastname: Dickinson
authors.forename: Terry
authors.initials: T
authors.lastname: Magnuson
mesh_terms: D000818:Animals; D002784:Cholesterol / Q000378:metabolism*; D015925:Cryopreservation; D005307:Fertilization in Vitro; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007178:Inbreeding; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008928:Mitochondria / Q000502:physiology; D018384:Oxidative Stress / Q000502:physiology; D013094:Spermatozoa / Q000502:physiology*
chemical_list: D002784:Cholesterol; D006861:Hydrogen Peroxide
keywords: acrosome reaction; cryopreservation; in vitro fertilization (IVF); oxidative stress; sperm capacitation