02716naa a2200277 a 450000100080000000500110000800800410001902400410006010000180010124502360011926000090035552017690036465000220213365000160215565300370217165300190220865300210222770000170224870000150226570000160228070000220229670000190231870000180233770000250235577300580238020850442023-01-27       2017    bl uuuu     u00u1 u    #d7 a10.1016/j.domaniend.2017.03.0032DOI1 aASCARI, I. J.  aAddition of insulin-like growth factor I to the maturation medium of bovine oocytes subjected to heat shockbeffects on the production of reactive oxygen species, mitochondrial activity and oocyte competence.h[electronic resource]  c2017  aAbstract 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 38.5C, or heat shock: 12 h at 41C followed by 12 h at 38.5C) 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 &gt 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 &gt 0.05). However, IGF-I increased (P &lt 0.05) the mitochondrial membrane potential and the production of ROS in oocytes and decreased (P &lt 0.05) the proportion of apoptotic cells in the ICM in blastocysts. Heat shock increased (P &lt 0.05) the proportion of TUNEL-positive oocytes and ROS production and reduced (P &lt 0.05) the mitochondrial membrane potential. Moreover, heat shock increased (P &lt 0.05) the apoptosis proportion in the ICM cells. In conclusion, supplementing IVM mediumwith 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.  aDNA fragmentation  aheat stress  aMitochondrial membrane potential  aROS production  aThermoprotection1 aALVES, N. G.1 aJASMIN, J.1 aLIMA, R. R.1 aQUINTAO, C. C. R.1 aOBERLENDER, G.1 aMORAES, E. A.1 aCAMARGO, L. S. de A.  tDomestic Animal Endocrinologygv. 60, p. 50-60, 2017.