Effects of ovarian stimulation on oocyte development and embryo quality

Swann, Kimberley Marie (2014) Effects of ovarian stimulation on oocyte development and embryo quality. PhD thesis, University of Nottingham.

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Ovarian stimulation plays a pivotal role in assisted reproductive therapies, to increase the number of embryos available for treatment; however, there is no clear consensus from meta-analyses in the literature which, if any, of the preparations in use are superior in terms of clinical outcomes. The aim of this thesis was to examine the effect of common human gonadotrophin preparations with different half lives and LH activity (hMG, rFSH and Pergoveris) on embryo quality and resulting offspring, compared to non- stimulated negative controls and positive PMSG treated controls, using the mouse model. The studies in this thesis indicated that an LH ceiling threshold is evident during folliculogenesis, where the use of long acting LH preparations resulted in higher numbers of fragmented oocytes, absent of cumulus cells (P<0.001), reduced expression of the pro and anti-angiogenic factors, MYHII and PEDF in cumulus cells (P<0.05), increased embryonic developmental arrest (P<0.001) and perturbed IGF2 (P<0.05) and VEGFA gene expression in resulting blastocysts (P<0.01), compared to negative controls. Use of preparations containing LH bioactivity resulted in offspring with altered total body weight trajectories and internal organ weight abnormalities (P<0.05), which were, in some instances, compounded by in vitro culture. In addition, we elucidated a relationship between FSH half life differences between urinary and recombinant preparations and embryo quality. The urinary human gonadotrophin preparation, hMG, could yield developmentally competent embryos at lower concentrations, than the recombinant Pergoveris treatment. In addition to FSH, these preparations contain LH and both low doses of preparations composed of short half life rFSH and rLH and high doses of preparations containing long acting LH bioactivity, resulted in the highest rates of developmental arrest. These groups were observed to have complete absence of H19 expression. The results of this thesis provide clear evidence that ovarian stimulation does negatively impact the embryo and subsequent offspring and provides support for an LH ceiling threshold, above which detrimental effects occur, both on in vitro embryo development and in vivo foetal development, which later effects postnatal growth.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Campbell, B.
Maalouf, W.
Jayaprakasan, M.
Raine-Fenning, N.
Keywords: Ovarian stimulation, Human gonadotrophin preparations, Mouse model, Embryology, Oocytes
Subjects: Q Science > QH Natural history. Biology > QH471 Reproduction. Life
Faculties/Schools: UK Campuses > Faculty of Medicine and Health Sciences > School of Clinical Sciences
UK Campuses > Faculty of Medicine and Health Sciences > School of Medicine
Item ID: 14233
Depositing User: EP, Services
Date Deposited: 17 Nov 2014 11:57
Last Modified: 13 Sep 2016 18:27
URI: http://eprints.nottingham.ac.uk/id/eprint/14233

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