5 PROPYLENE GLYCOL FEEDING SUPPLEMENTATION MODIFIES INSULIN-LIKE GROWTH FACTOR SYSTEM GENE EXPRESSION IN CUMULUS–OOCYTE COMPLEXES AND THE EXPRESSION OF SELECTED CANDIDATE GENES IN EMBRYOS PRODUCED IN VITRO IN FEED-RESTRICTED HEIFERS
G. Gamarra A B , C. Ponsart C , S. Lacaze B , F. Nuttinck D , P. Mermillod E , B. Le Guienne A , D. Monniaux F , P. Humblot G and A. A. Ponter H BA UNCEIA Département Recherche et Développement, Maisons Alfort, France;
B MIDATEST, Denguin, France;
C ANSES, Animal Health Laboratory, Maisons Alfort, France;
D INRA, UMR 1198 Biologie du Développement et Reproduction, Jouy-en-Josas, France;
E INRA, UMR7247, Physiologie de la Reproduction et des Comportements, Nouzilly, France;
F INRA, UMR85 Physiologie de la Reproduction et des Comportements, Nouzilly, France;
G Division of Reproduction, Department of Clinical Sciences, Faculty of Veterinary Medicine and Agricultural Sciences, Uppsala, Sweden;
H Université Paris Est, Ecole Nationale Vétérinaire d'Alfort, UMR 1198 Biologie du Développement et Reproduction, Maisons Alfort Cedex, France
Reproduction, Fertility and Development 27(1) 95-95 https://doi.org/10.1071/RDv27n1Ab5
Published: 4 December 2014
Abstract
Dietary supplementation with propylene glycol (PG) increases the rate of grade 1 embryos produced from feed restricted females (Gamarra et al. 2014 Reprod. Fertil. Dev.). The aim of this study was to evaluate if a PG feeding supplement could modify the expression profile of selected candidate genes that are important for in vitro embryo development and the gene expression patterns of the insulin-like growth factor (IGF) system in oocytes and cumulus cells in feed-restricted heifers. Feed-restricted heifers (n = 16, growth rate of 600 g day–1) received a single daily drench of 400 mL of water (group restricted, R) from Day 1 to Day 9 of a first synchronized oestrous cycle followed by 400 mL of PG from Day 1 to Day 9 of the second synchronized oestrous cycle (group restricted + PG, RPG). Ovum pick-up (OPU) was performed following superovulation, on Day 5 of the oestrous cycle to produce embryos in vitro and on Day 9 without superovulation to obtain oocytes and cumulus cells. The same protocol was used in control animals (n = 6, growth rate of 800 g day–1). Real-time PCR was used to determine the relative abundance of genes involved in lipid metabolism and storage (PLIN2, SCD), energy metabolism (ATP5A1, GLUT1), membrane permeability (AQP3), epigenetic marks (DNMT3a), apoptosis (BAX, TP53), and protein processing (HSPA9B) in grade 1 blastocysts, IGF1, IGF1R, IGFBP2, IGFBP4 in cumulus cells, and IGF1R and IGFBP2 in oocytes. Mann-Whitney nonparametric tests were performed to analyse gene expression results. The expression of PLIN2, ATP5A1, GLUT1, AQP3, DNMT3a, BAX, and HSPA9B were decreased in embryos collected from restricted compared with control animals. The expression levels of these genes were restored when females were supplemented with PG. The expression of TP53 and SCD were not affected. In cumulus cells, the expression levels of IGF1, IGF1R, and IGFBP4 were decreased in restricted compared with control animals. The expression levels of IGF1 and IGF1R were restored with PG supplementation. No differences were observed for the IGFBP2 gene. In the oocytes, no differences were observed for the expression levels of IGF1R and IGFBP2 genes. In conclusion, this work shows for the first time that feed restriction and dietary supplementation by PG in heifers produced changes in gene expression in blastocysts and modified the pattern of the IGF system in cumulus cells. These results suggest the existence of an epigenetic regulation induced by PG during follicular growth, which can regulate the level of gene expression up to the blastocyst stage. In general, PG supplementation of feed-restricted donors restored gene expression at the levels observed after normal feeding.
