Cryosurvival of rabbit embryos obtained after superovulation with corifollitropin alfa with or without LH

Abstract

The efficiency of an embryo bank depends on provision of optimal conditions for recovery, cryopreservation and transfer to a breed or strain. In this sense, increasing the number of embryos available using superovulation should improve the cryobank efficiency. However, vagueness of response to conventional protocols to control or increase ovarian response and the quality of oocytes and embryos and their cryotolerance remain a challenge. The aim of our study was to evaluate the effect of corifollitropin alpha (CTP) and a recombinant human FSH (rhFSH), alone or supplemented with rhLH, on embryo cryosurvival by in vitro development and OCT4 and NANOG mRNA abundance at blastocyst stage and offspring rate. In vitro development of vitrified embryos was not significantly affected by superstimulation with or without rhLH supplementation, resulting in similar development rates to those of the control groups (fresh and vitrified embryos from non-superstimulated donor does). Blastocysts developed from vitrified embryos showed higher levels of OCT4 transcript abundance than fresh control, while NANOG transcript abundance was only higher in the blastocysts developed from vitrified embryos after superstimulation treatment in comparison with control groups. The implantation and offspring rates at birth were negatively affected by supplementation with rhLH. Both rhFSH or CTP vitrified embryo groups showed an implantation rate similar to those of the control groups, but an offspring rate lower than control. In conclusion, embryos produced using corifollitropin alpha did not compromise the cryosurvival of vitrified embryos in the rabbit. In addition, this study points out the negative effect of rhLH supplementation in terms of offspring rate on embryo vitrification.

A single injection of corifollitropin alfa supplemented with human chorionic gonadotropin increases follicular recruitment and transferable embryos in the rabbit

“…In addition, it seemed that hCG allowed a highly effective and more stable occupancy of LH/hCG receptors than rhLH. Moreover, our results indicate that superovulation treatment using hCG supplementation does not compromise the in vivo embryo cryosurvival, contrary to what was observed in a previous study using rhLH supplementation (Vicente et al, ). On the other hand, regardless the morphological assessment of the embryo can provide certain clues about the quality, the potential for in vitro development and certainly the survival rate at birth are determinant to identify an effective ovarian stimulation protocol.…”

“…The FSH‐CTP introduction reduces the number of injections needed for ovarian stimulation and permits a simpler approach. FSH‐CTP has been used successfully in women, cattle and rabbits (Boostanfar et al, ; Carvalho et al, ; Devroey et al, ; Fauser et al, ; Vicente, Viudes‐de‐Castro, Cedano‐Castro, & Marco‐Jiménez, ; Viudes‐de‐Castro et al, ). Although FSH is the main regulator of ovarian follicle growth and maturation, LH induces key changes in both oocyte and follicular cells, that contribute to suitable oocyte competence acquisition, with a prominent role in the process of ovulation and in subsequent fertilization and implantation process.…”

Multigenerational Effects of a Complex Human-Relevant Exposure during Folliculogenesis and Preimplantation Embryo Development: The FEDEXPO Study

“…To obtain at least 6 F1 adult offspring per group and per sex to breed until adulthood, we account for 8 pups per group and per sex after the embryo transfer procedure. Hypothesizing a decrease of 33% in the embryo implantation rate in the exposed groups (40% instead of 60% in the NE group [ 40 ]), at least 48 embryos in the 2 exposed groups and 36 in the NE group must be transferred into, respectively, 4, 4 and 3 non-exposed foster mothers (with 6 embryos per uterine horn). This will require 6 F0 females in the exposed groups and 5 in the NE group for each 2 sets of experiment.…”