Role of arachidonic acid cascade in Rhinella arenarum oocyte maturation

ORTIZ, ME; ARIAS TORRES, AJ; ZELARAYAN, LI

ZYGOTE

CAMBRIDGE UNIV PRESS

Lugar: Cambridge; Año: 2014 vol. 25 p. 1 - 12

0967-1994

?Role of arachidonic acid cascade in Rhinella arenarum oocyte maturation?     Maria Eugenia Ortiz1, Ana Josefina Arias Torres2 and Liliana Isabel Zelarayán2 1 Centro de Referencias para Lactobacilos (CERELA)-CONICET. Chacabuco 145. Tucumán. Argentina.2 Instituto de Biología. Facultad de Bioqca., Qca. y Farmacia. INSIBIO-UNT. Chacabuco 461. Tucumán. Argentina.   Key words: arachidonic acid cascade, prostaglandins, Rhinella arenarum, oocyte maturation Running Title: Arachidonic acid in amphibian oocyte maturation Correspondence: All correspondence to: Liliana Isabel Zelarayán. Instituto de Biología. Facultad de Bioqca., Qca. y Farmacia. INSIBIO-UNT. Chacabuco 461, 4000. San Miguel de Tucumán, Tucumán. Argentina. Tel: +549 381 4247752 Int. 7093. Fax: +549 381 4247752 Int. 7004. e-mail: lzelarayan@fbqf.unt.edu.ar     Abstract   There are no studies documenting prostaglandins (PGs) production or their role in Rhinella arenarum oocyte maturation. We analyze the effect of AA and PGs on maturation, activation and pronuclear formation in R. arenarum oocytes. Our results demonstrated that AA was capable of inducing maturation in time- and dose-dependent manner. AA-induced maturation was inhibited by indomethacin. We demonstrated that PGs from AA hydrolysis such as PGF2a and, to a lesser extent, PGE2, induce oocytes maturation. Oocyte maturation in response to PGF2a was similar to that produced by progesterone (P4). Oocyte response to PGE1 was scarce. R. arenarum oocyte PGF2a -induced maturation showed a seasonal variation. During February-June, oocytes presented low sensitivity to PGF2a. In following periods, this response increased until a maximum was reached during October-January, a close temporal correlation with oocyte response to P4 being observed. The effect of PGF2a on maturation was verified by analyzing 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 PGF2a induces GVBD and meiosis resumption until metaphase II. In turn, oocytes matured by the action of PGF2a were able to form pronuclei after fertilization in a similar way to oocyte maturated by P4. In our amplification experiments, transformation of pre-MPF to MPF was observed when oocytes were treated with PGF2a. In summary, our results illustrate the participation of AA cascade and its metabolites in maturation, activation and pronuclei formation in R. arenarum.