Delipidação química na produção in vitro e criopreservação de embriões bovinos
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Data
2018-09-13
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Universidade Federal de Goiás
Resumo
Chemical delipidation has been used as an alternative to improve the cryotolerance of in
vitro produced embryos (IVP). The aim of this study was evaluate the effect of L-carnitine (LC) on
the development and survival of vitrified IVP bovine embryos by the Cryotop method in the first
assay, and in the second trial the effect of LC and Forskolin on Cryotop cryopreserved embryos
Experiment 1), or by modified slow freezing (Experiment 2), so mitochondrial activity,
intracytoplasmic lipid (LI) content, cellular apoptosis (NCA) and hatching after heating were
evaluated. In the first essay LC was used at the concentration of 0,6 mg/mL in maturation culture
medium (IVM), embryo culture (IVC) and / or post-thawing (REC), in four treatments: without LC
(Control), LC added to CIV (LCiv), LC to CIV + LC to REC (LCivR), and LC to MIV / CIV + LC
to REC (LMivCR). The addition of LC increased the production of blastocysts in D7 by 28.6%
(LCiv) and the amount of embryos grade I by 36.9% (LCivR), the re-expansion rate in 22,7% and
hatching in 20.1% (LCiv), and mitochondrial activity was 1.9 times higher (P <0.001) (LCivR)
than Control. The LI quantity was 29% lower in LCiv and LCivR and 50.2% in LMivCR compared
Control (P <0.001). In the second experiment the embryos were cultured without addition of
delipidators (Control), in the presence of 10μM of Forskolin added to the IVC in D5 (FORSK) or
L-carnitine (0.6 mg / mL) added to the IVC and in post-thawing (LC). LC supplementation
increased the production of blastocysts in D7 by 22.0% and grade I embryos by 30.1% (P <0.05),
in relation to Control and FORSK. In Experiment 1, the re-expansion rate in LC increased (P
<0.05) 28.9% in relation to FORSK. In Experiment 2, two Control treatments were used for slow
freezing (Classic and Modified). Hatching after 48 hours was greater (P <0.05) in LC compared to
FORSK and Classical and Modified Controls (77.5%, 41.9%, 40.5%, 40.8% respectively). In the
LC treatment, there was a decrease (P <0.05) of 64.7% in the degenerate embryo rate in relation to
the Classical Control. Treatment with delipidators reduced LI content (P <0.001) by 2.2 fold in
FORSK and four times in the LC compared to Control. The addition of 0.6 mg / mL of L-carnitine
to the culture medium and the post-thawing increased the rate of in vitro production of bovine
embryos acting positively on mitochondrial potential, reducing the amount of intracellular lipids
and cellular apoptosis and increasing cryotolerance of embryos submitted to the modified slow
freezing protocol.
Descrição
Palavras-chave
L-carnitina , Forskolin , PIVE , Congelamento lento , Embriões bovinos , L-carnitine , Forskolin , IVP , Slow freezing , Bovine embryos
Citação
DIESEL, Tiago Omar. Delipidação química na produção in vitro e criopreservação de embriões bovinos. 2018. 92 f. Tese (Doutorado em Zootecnia) - Universidade Federal de Goiás, Goiânia, 2018.