Melatonin reduces apoptotic cells, <scp>SOD</scp>2 and <scp>HSPB</scp>1 and improves the in vitro production and quality of bovine blastocysts

Abstract

Contents Effects of adding different concentrations of melatonin (10 −7 , 10 −9 and 10 −11 M) to maturation (Experiment 1; Control, IVM + 10 −7 , IVM + 10 −9 , IVM + 10 −11 ) and culture media (Experiment 2; Control, IVC + 10 −7 , IVC + 10 −9 , IVC + 10 −11 ) were evaluated on in vitro bovine embryonic development. The optimal concentration of melatonin (10 −9 M) from Experiments 1–2 was tested in both maturation and/or culture media of Experiment 3 (Control, IVM + 10 −9 , IVC + 10 −9 , IVM / IVC + 10 −9 ). In Experiment 1, maturated oocytes from Control and IVM + 10 −9 treatments showed increased glutathione content, mitochondrial membrane potential and percentage of Grade I blastocysts (40.6% and 43%, respectively). In Experiment 2, an increase in the percentage of Grade I blastocysts was detected in IVC + 10 −7 (43.5%; 56.7%) and IVC + 10 −9 (47.4%; 57.4%). Moreover, a lower number and percentage of apoptotic cells in blastocysts were observed in the IVC + 10 −9 group compared to Control (3.8 ± 0.6; 3.6% versus 6.1 ± 0.6; 5.3%). In Experiment 3, the IVC + 10 −9 treatment increased percentage of Grade I blastocysts with a lower number of apoptotic cells compared to IVM / IVC + 10 −9 group (52.6%; 3.0 ± 0.5 versus 46.0%; 5.4 ± 1.0). The IVC + 10 −9 treatment also had a higher mRNA expression of antioxidant gene ( SOD 2) compared to the Control, as well as the heat shock protein ( HSPB 1) compared to the IVM + 10 −9 . Reactive oxygen species production was greater in the IVM / IVC + 10 −9 treatment group. In conclusion, the 10 −9 M concentration of melatonin and the in vitro production phase in which it is used directly affected embryonic development and quality.