Prorenina e receptor de (pro)renina no período peri-ovulatório bovino

• Autor(a) principal: Dau, Andressa Minussi Pereira
• Data de Publicação: 2013
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Manancial - Repositório Digital da UFSM
• dARK ID: ark:/26339/0013000011hh8
• Texto Completo: http://repositorio.ufsm.br/handle/1/10149
• topic: Angiotensina II; Alisquireno; Retomada da meiose; Ovulação; Angiotensin II; Aliskiren; Resumption of meiosis; Ovulation; CNPQ::CIENCIAS AGRARIAS::MEDICINA VETERINARIA

The objectives of this study were: to determine the presence of prorenin and the receptor of (pro)renin [(P)RR] in cumulus cells (CC) and oocytes; evaluate the role of prorenin in the resumption of oocyte meiosis, ovulation and on levels of plasma progesterone (P4). The mRNA expression of prorenin and (P) RR was evaluated in oocytes and cumulus cells of the bovine species. The mRNA of prorenin and (P)RR was detected in CC, in oocytes only mRNA expression of (P)RR was found. The role of prorenin in the resumption of meiosis was determined from 3 experiments using a co-culture of cumulus-oocyte complex (COC) and follicular halves. In the first experiment, three different concentrations of prorenin (10-10, 10-9, and 10-8M) were tested, which stimulated the resumption of meiosis similar to the positive control and angiotensin II (Ang II). In experiment 2, the co-culture was supplemented with prorenin (10-10M) and aliskiren (direct inhibitor of renin, 10-3M, 10-5M and 10-7M). The aliskiren blocked the resumption of meiosis-induced by prorenin in all concentrations tested. The aliskiren (10-5M and 10-7M) was also evaluated in isolation in a culture system of COCs without follicular halves and the rate of oocytes that resumed meiosis was not different of the positive control. The third experiment was conducted to evaluate the stimulation of meiosis resumption by prorenin independent of Ang II using the combination of prorenin (10-10M) and saralasin [nonspecific Ang II receptor antagonist - Sar (10-5M)], which obtained a rate of oocytes at metaphase I (MI) similar to the positive control and treatments of AngII and prorenin. The prorenin also resumed the oocyte meiosis in a culture system of COCs suplemmented with forskolin, wicth blocks the meiosis by intracellular cAMP accumulation. To evaluate the regulation of (P)RR mRNA in the theca and granulosa cells by LH, cows who achieved follicular diameter ≥12mm after synchronization were submitted to the ovariectomy 0, 3, 6, 12 and 24 hours after GnRH analogue treatment. There was a higher mRNA expression of (P)RR in the theca cells at hour 6; and at hour 3 in the granulosa cells. The effect of (P)RR in ovulation and plasma P4 during luteinization was observed cows that were synchronized and induced by GnRH analogue (IM) associated for intrafollicular aliskiren (10-5M) or PBS (0hour/0day) and the ovulation was evaluated at 24, 48 and 72 hours by ultrasound, wicth was not different of the control (PBS). The leves of plasma P4 was analysed at day 6 and 8 after GnRH and intrafollicular treatment only in the cows that ovulated. The intrafollicular (P)RR blocks decreased plasma P4 at day 6. It was concluded that the prorenin / (P)RR participates in the peri-ovulatory period: in the resumption of oocyte meiosis independently of AngII, in the ovulation by LH stimulation to (P)RR mRNA and in the P4 synthesis during luteinization.