Addition of insulin-like growth factor I to the maturation medium of bovine oocytes subjected to heat shock: effects on the production of reactive oxygen species, mitochondrial activity and oocyte competence

I J Ascari; N G Alves; J Jasmin; R R Lima; C C R Quintão; G Oberlender; E A Moraes; L S A Camargo

doi:10.1016/j.domaniend.2017.03.003

Addition of insulin-like growth factor I to the maturation medium of bovine oocytes subjected to heat shock: effects on the production of reactive oxygen species, mitochondrial activity and oocyte competence

Domest Anim Endocrinol. 2017 Jul:60:50-60. doi: 10.1016/j.domaniend.2017.03.003. Epub 2017 Mar 25.

Authors

I J Ascari¹, N G Alves², J Jasmin³, R R Lima⁴, C C R Quintão⁵, G Oberlender⁶, E A Moraes⁷, L S A Camargo⁵

Affiliations

¹ Department of Animal Science, Federal University of Lavras, Lavras, Minas Gerais, Brazil.
² Department of Animal Science, Federal University of Lavras, Lavras, Minas Gerais, Brazil. Electronic address: nadja@dzo.ufla.br.
³ NUMPEX-Bio, Universidade Federal do Rio de Janeiro, Campus Duque de Caxias, Duque de Caxias, Rio de Janeiro, Brazil.
⁴ Department of Exact Sciences, Federal University of Lavras, Lavras, Brazil.
⁵ Brazilian Agricultural Research Corporation - Dairy Cattle, Juiz de Fora, Minas Gerais, Brazil.
⁶ Federal Institute of Education, Science and Technology of South Minas Gerais, Muzambinho, Minas Gerais, Brazil.
⁷ School of Animal Science, Federal University of Vale do São Francisco, Petrolina, Pernambuco, Brazil.

PMID: 28445838
DOI: 10.1016/j.domaniend.2017.03.003

Abstract

This study was performed to investigate the effects of insulin-like growth factor-I (IGF-I) addition to in vitro maturation (IVM) medium on apoptosis, mitochondrial membrane potential, ROS production, and developmental competence of bovine oocytes subjected to heat shock. Two temperatures (conventional: 24 h at 38.5°C, or heat shock: 12 h at 41°C followed by 12 h at 38.5°C) and 3 IGF-I concentrations (0, 25, and 100 ng/mL) were tested during IVM. The oocytes were then fertilized in vitro, and the presumptive zygotes were cultured until reaching the blastocyst stage. There was no interaction between temperature and IGF-I concentration for any variable evaluated (P > 0.05). The addition of IGF-I did not alter the proportion of nuclear maturation, TUNEL-positive oocytes and caspase-3 activity, or blastocyst proportion on Days 7 and 8 post-fertilization. Furthermore, the total number of cells and the number of cells in the inner cell mass (ICM) in the blastocyst were not altered (P > 0.05). However, IGF-I increased (P < 0.05) the mitochondrial membrane potential and the production of ROS in oocytes and decreased (P < 0.05) the proportion of apoptotic cells in the ICM in blastocysts. Heat shock increased (P < 0.05) the proportion of TUNEL-positive oocytes and ROS production and reduced (P < 0.05) the mitochondrial membrane potential. Moreover, heat shock increased (P < 0.05) the apoptosis proportion in the ICM cells. In conclusion, supplementing IVM medium with IGF-I may increase the mitochondrial membrane potential and ROS production in oocytes and decrease apoptosis in the ICM in blastocysts. Heat shock for 12 h compromised oocyte developmental competence and increased apoptosis within the ICM cells of the blastocysts.

Keywords: DNA fragmentation; Heat stress; Mitochondrial membrane potential; ROS production; Thermoprotection.

Publication types

Randomized Controlled Trial
Research Support, Non-U.S. Gov't

MeSH terms

Animals
Apoptosis / drug effects
Cattle*
Embryo Culture Techniques
Fertilization in Vitro / veterinary
Hot Temperature*
In Vitro Oocyte Maturation Techniques / veterinary
Insulin-Like Growth Factor I / pharmacology*
Mitochondria / physiology*
Oocytes / drug effects
Oocytes / physiology*
Reactive Oxygen Species / metabolism*

Substances

Reactive Oxygen Species
Insulin-Like Growth Factor I