Relationship of vascular perfusion of the wall of the preovulatory follicle to in vitro fertilisation and embryo development in heifers

Abstract

The effect of the extent of vascular perfusion of the wall of the preovulatory follicle on in vitro cleavage rate of the recovered oocyte and embryo development to >8 cells was studied in 52 heifers. Heifers received a luteolytic dose of prostaglandin F2α (PGF2α) when the largest follicle was ≥11 mm. An ovulation-inducing injection of GnRH was given 36 h later (hour 0), and collection of follicular fluid and the oocyte was done at hour 26. Vascular perfusion of the follicular wall was assessed by colour Doppler ultrasonography at hours 0 and 26. Each of the recovered oocytes (41/52; 79%) was mature (extruded polar body). Cleavage and embryo development were assessed at 48 h and 120 h respectively, after in vitro fertilisation (IVF). The percentage of cleaved oocytes and >8 cell embryos was 80% (31/39) and 55% (17/31) respectively. Vascular perfusion of the follicular wall was greater (lower pulsatility index; P<0.001) for follicles that produced cleaved versus non-cleaved oocytes and greater (P<0.04) for follicles that produced >8 cell versus ≤8 cell embryos. Percentage of follicular wall with Doppler signals of blood flow was greater (P<0.001) for >8 cell versus ≤8 cell embryos. Follicular-fluid concentration of free IGF1 was lower for cleaved oocytes (P<0.001) and >8 cell embryos (P<0.05), and oestradiol was lower (P<0.05) for >8 cell embryos. Results supported the hypothesis that greater vascular perfusion of the wall of the preovulatory follicle was positively associated with IVF and embryo development.

In vivo oocyte developmental competence is reduced in lean but not in obese superovulated dairy cows after intraovarian administration of IGF1

“…In this model, the heifers were still growing and endogenous concentrations of IGF1 were probably higher than in their adult counterparts, with no deficit of IGF1, unless they are under a catabolic disease state (Velazquez et al 2008). Our results also agree with previous studies carried out in women (Wang et al 2006) and heifers (Nicholas et al 2005, Siddiqui et al 2009, where oocytes obtained from follicles with high IGF1 bioavailability (i.e. more free IGF1 or less IGFBPs) displayed impaired developmental competence in vitro.…”

Luteal blood flow and concentrations of circulating progesterone and other hormones associated with a simulated pulse of 13,14-dihydro-15-keto-prostaglandin F2α in heifers

“…The intra-and interassay CV and sensitivity respectively were 9.2%, 10.5% and 0.03 ng/ml for LH and 6.5%, 4.8% and 0.07 ng/ml for FSH. Plasma concentrations of oestradiol were measured as described and validated in our laboratory (Siddiqui et al 2009) using a commercially available RIA kit (Double Antibody Oestradiol: Diagnostic Products Corporation). The intraassay CV and sensitivity were 14.9% and 0.1 pg/ml respectively.…”

Follicle and hormone dynamics in single versus double ovulating heifers

“…The standards and antibodies were purchased from A F Parlow (National Hormone and Pituitary Program, Torrance, CA, USA). Plasma concentrations of E 2 were measured as described and validated in our laboratory (Siddiqui et al 2009), using a commercially available RIA kit (Double Antibody Estradiol: Diagnostics Products Corporation, Los Angeles, CA, USA). The intra-and interassay coefficients of variation and mean sensitivity respectively, were 9.1%, 5.2% and 0.1 ng/ml for LH; 6.1%, 8.0%, and 0.02 ng/ml for FSH; and 14.1%, 7.7% and 0.1 pg/ml for E 2 .…”