Effects of resolvin D1 on bovine oocytes, cumulus cells, and in vitro embryo development

This study evaluated the cytoprotective, antioxidant, and anti-inflammatory effects of Resolvin D1 (RvD1) during bovine oocyte in vitro maturation (IVM) and its impact on embryo development. Four experiments were performed: (1) cytoprotective effect by oocyte nuclear maturation, mitochondrial density, and cumulus cell (CC) DNA damage; (2) antioxidant activity by intracellular reactive oxygen species (ROS) and glutathione (GSH) concentration in CCs and oocytes; (3) anti-inflammatory action by mRNA expression of IL-1β, IL-6, and TNF-α in CCs; and (4) developmental competence by cleavage, blastocyst, and hatching rate. In Experiments 1-2, IVM supplementation were: control (0.1 % ethanol), 25, 50, or 75 pg RvD1/mL; Experiments 3-4 IVM supplementation were: control and 50 pg RvD1/mL. Cumulus oocyte-complexes underwent IVM for 24 h at 39 °C in 5 % CO₂. In experiment 1, RvD1 did not alter nuclear maturation or CC DNA damage. Mitochondrial density was marginally greater at 25 pg RvD1/mL compared with control. In experiment 2, in CC, ROS were lesser with 50 and 75 pg RvD1/mL than control; in oocytes, ROS was reduced in all RvD1 groups. No difference was observed in GSH in CC; in oocytes, GSH level was lesser in 25 and 75 pg RvD1/mL than control. In experiment 3, RvD1 did not affect IL-1β, IL-6, or TNF-α mRNA expression. In experiment 4, RvD1 had no effect on cleavage, day-7 or total blastocyst, or hatching rate. Resolvin D1 may help modulate ROS during IVM. Further studies should assess its potential synergistic effects with other modulators or under inflammatory conditions.