In vitro survival, growth, and maturation of sheep oocytes from secondary follicles cultured in serum-free conditions: impact of a constant or a sequential medium containing recombinant human FSH

Barros, V.R.P.; Monte, A.P.O.; Lins, T.L.B.G.; Santos, J.M.; Menezes, V.G.; Cavalcante, A.Y.P.; Araújo, V.R.; Gouveia, B.B.; Matos, M.H.T.

In vitro survival, growth, and maturation of sheep oocytes from secondary follicles cultured in serum-free conditions: impact of a constant or a sequential medium containing recombinant human FSH

2018

This study evaluated the in vitro development and maturation of ovine oocytes from secondary follicles cultured in serum-free medium containing fixed or sequential concentrations of recombinant human FSH (rhFSH). Follicles were cultured in α-MEM+ alone or with constant (500, 750, or 1,000 ng/mL) or sequential concentrations of rhFSH (seq. 1: day 6 = 500; day 12 = 750; day 18 = 1,000 ng/mL and seq. 2: day 6 = 100; day 12 = 500; day 18 = 1,000 ng/mL). At the end of the experiment, follicular survival was higher (P < 0.05) in 750 ng/mL rhFSH than the control and 1,000 ng/mL rhFSH. As early as day 6 of culture, antral cavity formation was observed in all treatments. Follicular diameter increased progressively and significantly in all treatments throughout 18 d of culture. Furthermore, addition of rhFSH to the medium promoted a significant increase in the percentage of fully grown oocytes in all treatments compared to α-MEM+. Mitochondrial activity was higher in rhFSH treatments than in the control, except in rhFSH seq. 2 (P < 0.05). Maturation rates increased in oocytes from intact follicles cultured in 750 ng/mL rhFSH compared to the control (P < 0.05). In conclusion, rhFSH at 750 ng/mL maintained the survival of secondary follicles cultured in serum-free medium, improved oocyte growth, mitochondrial activity, and oocyte maturation.

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