Abstract

GOTTARDI, F.P. et al. Effects of cumulus cells and cysteamine during bovine oocyte in vitro maturation on meiosis progression and acquisition of developmental competence. Arq. Bras. Med. Vet. Zootec. [online]. 2012, vol.64, n.2, pp. 245-252. ISSN 0102-0935.  http://dx.doi.org/10.1590/S0102-09352012000200001.

Cumulus-oocyte complexes (COC), denuded oocytes (DO) and DO co-cultured with cumulus cells in suspension (DO+CC) were in vitro matured (IVM) in the presence or absence of cysteamine (50mM). A beneficial effect of cysteamine was observed during IVM, because the nuclear maturation in the COC cysteamine group was higher than in COC control (P<0.05). In the control group, the absence of CC during IVM impaired nuclear maturation in DO when compared to COC (P<0.05), but cysteamine restored the ability of meiosis progression in DO, making them similar to COC (P>0.05). The coupling between oocytes and CC during IVM proved to be essential for the acquisition of oocyte competence to support early embryonic development, as COC had higher percentages of blastocyst and hatching when compared to DO and DO+DC (P<0.05). However, the inclusion of cysteamine in the IVM culture did not restore the acquisition of competence in DO and DO+DC, which remained similar to the control group (P>0.05). It is concluded that cysteamine in the IVM culture improves the nuclear maturation in COC and restores the progression ability of meiosis in DO. However, in the concentration used in this study, cysteamine does not promote a beneficial effect on embryo development.

Keywords : cattle; cumulus cells; cysteamine; in vitro maturation; oocyte.