Alpha-linolenic acid treatment during oocyte maturation enhances embryonic development by influencing mitogen-activated protein kinase activity and intraoocyte glutathione content in pigs

摘要

The purpose of this study was to examine the effects of alpha-linolenic acid (ALA) treatment during in vitro maturation (IVM) on nuclear maturation, intraoocyte glutathione (GSH) content, meiotic progression, and developmental competence after parthenogenesis (PA) and somatic cell nuclear transfer (SCNT) in pigs. Medium-199 containing 10% (vol/vol) porcine follicular fluid (PFF; PPF control) or 0.4% (wt/vol) fatty acid-free BSA (BSA control) was used for IVM. The proportion of oocytes reaching the metaphase II (MII) stage was not influenced by ALA treatment at various concentrations (50, 100, and 200 mu M). However, treatment with 100 mu M ALA significantly increased (P 0.05) intraoocyte GSH content (1.19 vs. 1.00 and 0.92 pixels per oocyte, comparing the treated oocytes, BSA control, and PFF control, respectively) and embryonic development to the blastocyst stage after PA (47.1 vs. 35.5 and 35.2%) and SCNT (31.4 vs. 23.9 and 24.3%). ALA treatment (100 mu M) accelerated oocyte maturation, and a higher proportion of ALA-treated oocytes (89.6%) reached the MII stage than did the untreated controls (75.5%) at 33 h of IVM. Mitogen-activated protein kinase kinase inhibitor (U0126) treatment during IVM inhibited nuclear maturation and embryonic development after PA. However, 100 mu M ALA completely counteracted the suppressive effect of U0126 on nuclear maturation and partially counteracted the effect on blastocyst formation. Our results demonstrate that treatment with 100 mu M ALA during IVM improves developmental competence by accelerating nuclear maturation and also influencing cytoplasmic maturation, such as increased GSH content in IVM oocytes.