title: 9-cis retinoic acid improves developmental competence and embryo quality during in vitro maturation of bovine oocytes through the inhibition of oocyte tumor necrosis factor-α gene expression.
abstract: Retinoic acid (RA; all-trans RA and 9-cis RA) enhances embryo developmental competence and quality through multiple mechanisms affecting the oocyte and preimplantation embryo. Folliculogenesis and oocyte maturation are influenced by tumor necrosis factor-α (TNF-α) via inhibition of aromatase activity and estradiol secretion in granulosa cells. Retinoic acid inhibits TNF-α production in various cell lines. The aim of the present study was to determine whether oocyte TNF-α concentrations regulate developmental competence and embryo quality and if the beneficial effects of 9-cis RA are mediated through attenuation of oocyte TNF-α production. Bovine cumulus oocyte complexes collected from abattoir ovaries were matured in maturation medium in the absence (control) or presence of 5 nM 9-cis RA (RA), 100 ng/mL of recombinant bovine TNF-α (TNF), or 5 nM 9-cis RA + 100 ng/mL of recombinant bovine TNF-α (RA+TNF). Oocytes were subsequently collected for gene expression analysis or subjected to in vitro fertilization and culture. Apoptosis and gene expression were analyzed in d-8 blastocysts. Results indicated that 9-cis RA downregulated (P < 0.01) both basal and TNF-α-induced TNF-α mRNA in oocytes (1.0-fold in control, 0.4-fold in RA, 2.1-fold in TNF, and 0.7-fold in RA+TNF). The 9-cis RA increased (P < 0.001) blastocyst development rates (37.1 ± 6.9 vs. 23.6 ± 8.0%) and total cell number (138.4 ± 19.2 vs. 120.2 ± 24.5) and reduced (P < 0.001) the percentage of apoptotic cells (3.3 ± 2.0 vs. 5.6 ± 2.3%) compared with controls. Expression of caspase 3 (0.4- vs. 1.0-fold) and TNF-α (0.4- vs. 1.0-fold) mRNA was downregulated (P < 0.05) in RA-treated blastocysts compared with controls. Moreover, 9-cis RA rescued (P < 0.001) development rates (24.5 ± 11.1 vs. 15.6 ± 9.0%), increased total cell number (124.6 ± 36.5 vs. 106.9 ± 31.1), and reduced apoptosis (5.8 ± 2.0 vs. 8.1 ± 3.1%) in blastocysts exposed to TNF-α (TNF group). Caspase 3 (0.8-fold in RA+TNF vs. 2.2-fold in TNF) and TNF-α (0.3-fold in RA+TNF vs. 2.8-fold in TNF) mRNA expression was attenuated (P < 0.05) in TNF-α-treated blastocysts. In conclusion, the present study suggests that 9-cis RA exerts its beneficial roles on oocyte developmental competence and embryo quality by attenuating oocyte TNF-α mRNA expression.
authors.affiliation: Division of Applied Life Science (BK21 Program), Graduate School of Gyeongsang National University, Gyeongsang National University, Jinju 660-701, Republic of Korea.
authors.forename: G K
authors.initials: GK
authors.lastname: Deb
authors.forename: S R
authors.initials: SR
authors.lastname: Dey
authors.forename: J I
authors.initials: JI
authors.lastname: Bang
authors.forename: S J
authors.initials: SJ
authors.lastname: Cho
authors.forename: H C
authors.initials: HC
authors.lastname: Park
authors.forename: J G
authors.initials: JG
authors.lastname: Lee
authors.forename: I K
authors.initials: IK
authors.lastname: Kong
mesh_terms: D000077556:Alitretinoin; D000818:Animals; D001755:Blastocyst / Q000187:drug effects / Q000378:metabolism; D053148:Caspase 3 / Q000187:drug effects; D002417:Cattle; D004622:Embryo, Mammalian / Q000187:drug effects*; D047108:Embryonic Development / Q000187:drug effects*; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D020287:In Situ Nick-End Labeling / Q000662:veterinary; D066298:In Vitro Techniques; D009865:Oocytes / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary; D014212:Tretinoin / Q000494:pharmacology*; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000502:physiology
chemical_list: D014409:Tumor Necrosis Factor-alpha; D000077556:Alitretinoin; D014212:Tretinoin; D053148:Caspase 3