Cassina 2015 Biol Reprod

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Cassina AM, Silveira P, Cantu L, Montes JM, Radi R, Sapiro R (2015) Defective human sperm cells are associated with mitochondrial dysfunction and oxidant production. Biol Reprod 93:119.

» PMID: 26447142 Open Access

Cassina AM, Silveira P, Cantu L, Montes JM, Radi R, Sapiro R (2015) Biol Reprod

Abstract: Infertility affects about 15% of the couples of reproductive age. The male factor is involved in nearly 50% of infertility cases. Defective human sperm function has been associated with evidence of high levels of reactive oxygen species (ROS) and a resultant loss of fertilizing potential in vivo and in vitro. Analogous to what has been observed in somatic cells, mitochondria are likely the major sources of ROS in sperm cells. In this study, we analyzed mitochondrial function using high-resolution respirometry, ROS production and footprints of oxidative and nitrative stress processes in intact human sperm cells. We showed that mitochondrial dysfunction (measured through the respiratory control ratio) was correlated with a decrease in human sperm motility. The samples analyzed presented nitro-oxidative modifications of proteins such as protein 3-nitrotyrosine that were observed mainly in the mid-piece (where mitochondria are localized) and in the sperm head. Semen samples presenting lower percentage of motile sperm showed higher amount of nitro-oxidative protein modifications than those with larger quantity of motile sperm. When spermatozoa were exposed to inhibitors of the respiratory mitochondrial function, in the presence of a nitric oxide flux (•NO), sperm produced potent nitro-oxidative species, i.e. peroxynitrite. This effect was observed in more than 90% of intact living sperm cells and in sperm mitochondrial fractions. These data suggest that dysfunctional mitochondria in sperm cells produce oxidants that may contribute to male infertility. These data provide the rationale for testing the potential of compounds that improve sperm mitochondrial function to treat male infertility.

Keywords: Mitochondria, Reactive oxygen species, Nitro-oxidative stress, Sperm motility and transport, Male infertility

O2k-Network Lab: UY Montevideo Radi R

Labels: MiParea: Respiration 

Stress:Oxidative stress;RONS  Organism: Human  Tissue;cell: Genital 

Coupling state: LEAK, ROUTINE, ET  Pathway: ROX  HRR: Oxygraph-2k