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Differential expression of insulin‐like growth factor family members in immature cumulus–oocyte complexes from dairy cows with different genotypes
Author(s) -
Lopes AC,
Palhão MP,
Fernandes CAC,
Sudano MJ,
Castilho ACS,
Caixeta ES
Publication year - 2017
Publication title -
reproduction in domestic animals
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.546
H-Index - 66
eISSN - 1439-0531
pISSN - 0936-6768
DOI - 10.1111/rda.13028
Subject(s) - biology , andrology , oocyte , zebu , insulin like growth factor , in vitro maturation , zoology , embryo , growth factor , genetics , receptor , medicine
Contents It has been evident the improvement of in vitro embryo production ( IVEP ) in dairy cows. Nevertheless, it is known that differences in the number and quality of oocytes between taurine and zebu females impact the efficiency and economic viability of IVEP . As the insulin‐like growth factor ( IGF ) system is related to follicular and oocyte development, we aimed to quantify mRNA abundance of IGF system members and pregnancy‐associated plasma protein‐A ( PAPPA ) in the cumulus–oocyte complexes ( COC s) of Gir, 1/2 Holstein × 1/2 Gir and Holstein cows. Four pools of 30 immature COC s from Gir, 1/2 Holstein × 1/2 Gir and Holstein cows were obtained by ovum pickup (OPU), and the oocytes and cumulus cells ( CC ) were mechanically separated and stored at −80°C. Total RNA was extracted from pools of 30 oocytes and their respective CC . Expression of target genes was assessed by real‐time RT ‐ PCR . In oocytes, the abundance of IGFR 1 mRNA was higher ( p < .05) in Gir cows compared with the other breeds. In contrast, in CC , mRNA encoding IGF 2 ( p < .05), IGFR 2 ( p < .05) and IGFBP 4 ( p < .01) was higher in Holstein donors compared with Gir and 1/2 Holstein × 1/2 Gir cows. Additionally, the abundance of PAPPA mRNA was higher in oocytes ( p < .001) and CC ( p < .01) in Gir and 1/2 Holstein × 1/2 Gir cows compared with the Holstein donors. In conclusion, the higher abundance of PAPPA mRNA in the oocytes and CC from Gir and cross‐breed donors combined with the low expression of IGFBP 4 in the CC suggests an enhancement of the bioavailability of IGF ‐free when compared with Holstein COCs.