Ortiz Maria Eugenia, Arias-Torres Ana Josefina, Zelarayán Liliana Isabel
Centro de Referencia para Lactobacilos (CERELA)-CONICET,Chacabuco 145,Tucumán,Argentina.
Instituto de Biología,Facultad de Bioqca.,Qca. y Farmacia,UNT. INSIBIO-CONICET,Chacabuco 461,Tucumán,Argentina.
Zygote. 2015 Aug;23(4):603-14. doi: 10.1017/S0967199414000240. Epub 2014 Jun 25.
There are no studies that document the production of prostaglandins (PGs) or their role in Rhinella arenarum oocyte maturation. In this study, we analysed the effect of arachidonic acid (AA) and prostaglandins (PGs) on maturation, activation and pronuclear formation in R. arenarum oocytes. Our results demonstrated that AA was capable of inducing maturation in time-dependent and dose-dependent manner. Arachidonic acid-induced maturation was inhibited by indomethacin. PGs from AA hydrolysis, such as prostaglandin F2α (PGF2α) and, to a lesser extent, PGE2, induced meiosis resumption. Oocyte maturation in response to PGF2α was similar to that produced by progesterone (P4). Oocyte response to PGE1 was scarce. Rhinella arenarum oocyte PGF2α-induced maturation showed seasonal variation. From February to June, oocytes presented low sensitivity to PGF2α. In following periods, this response increased until a maximum was reached during October to January, a close temporal correlation with oocyte response to P4 being observed. The effect of PGF2α on maturation was verified by analysing the capacity of oocytes to activate and form pronuclei after being injected with homologous sperm. The cytological analysis of activated oocytes demonstrated the absence of cortical granules in oocytes, suggesting that PGF2α induces germinal vesicle breakdown (GVBD) and meiosis resumption up to metaphase II. In turn, oocytes matured by the action of PGF2α were able to form pronuclei after fertilization in a similar way to oocyte maturated by P4. In microinjection of mature cytoplasm experiments, the transformation of pre-maturation promoting factor (pre-MPF) to MPF was observed when oocytes were treated with PGF2α. In summary, our results illustrated the participation of the AA cascade and its metabolites in maturation, activation and pronuclei formation in R. arenarum.
目前尚无研究记录前列腺素（PGs）的产生及其在阿根廷蟾蜍卵母细胞成熟过程中的作用。在本研究中，我们分析了花生四烯酸（AA）和前列腺素（PGs）对阿根廷蟾蜍卵母细胞成熟、激活和原核形成的影响。我们的结果表明，AA能够以时间和剂量依赖性方式诱导成熟。吲哚美辛可抑制花生四烯酸诱导的成熟。由AA水解产生的PGs，如前列腺素F2α（PGF2α）以及程度较轻的前列腺素E2（PGE2），可诱导减数分裂恢复。卵母细胞对PGF2α的成熟反应与孕酮（P4）诱导的相似。卵母细胞对前列腺素E1（PGE1）的反应较少。阿根廷蟾蜍卵母细胞PGF2α诱导的成熟表现出季节性变化。从2月到6月，卵母细胞对PGF2α的敏感性较低。在随后的时期，这种反应增加，直到10月至1月达到最大值，观察到与卵母细胞对P4的反应存在密切的时间相关性。通过分析卵母细胞注射同源精子后激活和形成原核的能力，验证了PGF2α对成熟的影响。对激活卵母细胞的细胞学分析表明，卵母细胞中不存在皮质颗粒，这表明PGF2α诱导生发泡破裂（GVBD）并使减数分裂恢复至中期II。反过来，经PGF2α作用成熟的卵母细胞在受精后能够以与经P4成熟的卵母细胞相似的方式形成原核。在显微注射成熟细胞质实验中，当用PGF2α处理卵母细胞时，观察到前成熟促进因子（pre-MPF）向MPF的转化。总之，我们的结果表明AA级联及其代谢产物参与了阿根廷蟾蜍的成熟、激活和原核形成过程。
