Effect of sperm lipid peroxidation on fertilization.
This study was aimed at determining, with homologous mouse gametes, whether a level of membrane lipid peroxidation insufficient to affect sperm motility parameters can alter sperm fertilizing potential. The addition of ferrous ions and ascorbic acid (Fe2+/ Asc) to mouse sperm suspensions increases the formation of thiobarbituric acid-reactive substances (TBARS), an indicator of lipid peroxide breakdown products, without significantly affecting the level of sulfhydryl groups. In the presence of Fe2+/Asc concentrations above > 0.4/2.0 mM, spermatozoa become immotile. However, at concentrations < or = 0.4/2.0 mM of Fe2+/Asc, i.e., conditions in which the TBARS formation is increased by < or = 4.6-fold over that of controls, motility remains unaffected for up to 3 hours. In the presence of 0.4/ 2.0 mM Fe2+/Asc, treated spermatozoa increase their fertilizing potential by 50%, as measured by the formation of two-cell embryos. This increase is not caused by improvements in sperm motility parameters (percentage, linearity, velocity, hyperactivation) or sperm capacitation. On the other hand, there is a significant increase in the capacity of mouse spermatozoa to bind to homologous zona pellucida. In conclusion, mild peroxidative conditions, that increase lipid peroxide formation 4.6-fold without significantly modifying free sulfhydryl groups and sperm motility parameters, improve the fertilizing potential of spermatozoa by increasing their binding capacity to zona pellucida.
Kodama
H
H
Urology Research Laboratory, Royal Victoria Hospital, Montreal, Canada.
Kuribayashi
Y
Y
Gagnon
C
C
D000818:Animals; D001205:Ascorbic Acid / Q000494:pharmacology; D005260:Female; D005296:Ferrous Compounds / Q000494:pharmacology; D005298:Fertility / Q000187:drug effects; D005306:Fertilization / Q000502:physiology*; D005307:Fertilization in Vitro; D015227:Lipid Peroxidation; D008297:Male; D008563:Membrane Lipids; D051379:Mice; D013075:Sperm Capacitation / Q000187:drug effects; D013081:Sperm Motility / Q000187:drug effects; D013084:Sperm-Ovum Interactions / Q000502:physiology; D013094:Spermatozoa / Q000378:metabolism*; D013438:Sulfhydryl Compounds / Q000032:analysis; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D015044:Zona Pellucida / Q000187:drug effects
D005296:Ferrous Compounds; D008563:Membrane Lipids; D013438:Sulfhydryl Compounds; D017392:Thiobarbituric Acid Reactive Substances; C020748:ferrous sulfate; D001205:Ascorbic Acid