title: L-carnitine improves hydrogen peroxide-induced impairment of nuclear maturation in porcine oocytes.
abstract: We investigated the effect of oxidative stress induced by hydrogen peroxide (H2 O2 ) on lipid peroxide (LPO) level and nuclear maturation in porcine oocytes cultured with or without cumulus cells. After 22 h of pre-culture, oocytes with attached cumulus cells (COC group) or denuded oocytes (DO group) were cultured with H2 O2 , and intra-oocyte H2 O2 and LPO levels were quantitatively analyzed using immunofluorescence. This is the first report evaluating LPO levels in porcine oocytes. After H2 O2 supplementation, the DO group showed severe accumulation of H2 O2 and LPO in the oocytes. Similarly, while inhibition of progression of nuclear maturation was observed in both groups, the effect was more severe in the DO group. These results demonstrate that cumulus cells reduce the accumulation of H2 O2 stress in oocytes. Furthermore, we attempted to reduce the oxidative stress by H2 O2 with L-carnitine, a H2 O2 scavenger. L-carnitine decreased H2 O2 and LPO levels in the oocytes in both groups, and improvement in the progression of impaired nuclear maturation was observed. These effects were different by the presence of cumulus cells. Our results provide that L-carnitine is useful for alleviating H2 O2 -induced oxidative stress by reducing LPO levels and improving the progression of nuclear maturation.
authors.affiliation: Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Yazaki
authors.affiliation: Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Hiradate
authors.affiliation: Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Hoshino
authors.affiliation: Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
authors.forename: Kentaro
authors.initials: K
authors.lastname: Tanemura
authors.affiliation: Laboratory of Animal Reproduction, Graduate School of Agricultural Science, Tohoku University, Sendai, Japan.
authors.forename: Eimei
authors.initials: E
authors.lastname: Sato
mesh_terms: D000818:Animals; D002331:Carnitine / Q000494:pharmacology*; D002467:Cell Nucleus / Q000502:physiology*; D054885:Cumulus Cells / Q000502:physiology; D005260:Female; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000009:adverse effects* / Q000378:metabolism; D008054:Lipid Peroxides / Q000378:metabolism; D009865:Oocytes / Q000166:cytology* / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology*; D013552:Swine
chemical_list: D016166:Free Radical Scavengers; D008054:Lipid Peroxides; D006861:Hydrogen Peroxide; D002331:Carnitine