Oxidative stress-inducible antioxidant adaptive response during prostaglandin F2α-induced luteal cell deathin vivo

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Abstract
Oxidative stress-induced antioxidant adaptive response would be particularly important to cells in high reactive oxygen species (ROS) environments. We aimed to determine the dynamic adaptive response of antioxidant enzymatic systems in sheep corpus luteum (CL) during PGF2α-induced luteal cell death. Activities of superoxide dismutase (SOD1 and SOD2), catalase (CAT), glutathione peroxidase (GPX) and glutathione reductase (GSR), and in situ DNA fragmentation were determined in CL at day 10 of the estrous cycle (0 h) and at 12, 24 or 48 h after PGF2α injection. A decrease in plasma progesterone concentration was first observed at 6 h after treatment (P < 0.05). Apoptotic cells were rarely observed in the CL at 0 h (less than 0.7%), and their incidence increased (P < 0.01) by 12 h post-PGF2α (11.7%) and remained thereafter elevated through 48 h. Activities of SOD1, SOD2, GPX and GSR were not changed at any time points after PGF2α treatment. CAT activity increased at 12 h (P < 0.01) and at 24 h (P < 0.05) after PGF2α treatment as compared to that at 0 h. These findings demonstrate that PGF2α induce luteal cell death without depressing the activity of antioxidant enzymes. It is suggested that transient increase in CAT activity is an adaptive response of the CL to oxidative stress induced by PGF2α.