title: A new selection criterion to assess good quality ovine blastocysts after vitrification and to predict their transfer into recipients.
abstract: The feasibility to accurately select viable embryos would be valuable for improving pregnancy rates and avoiding futile transfer attempts. The aim of our study was to assess if in vitro-produced embryo quality could be determined by the timing of blastocoelic cavity re-expansion after vitrification, warming, and in vitro culture using sheep as a model. Blastocysts were produced in vitro, vitrified/warmed, and cultured in TCM-199 plus 10% FCS for 72 hr. Embryos were divided into two groups: re-expanded within 8 hr (A) and from 8 to 16 hr (B) of IVC after warming. Fast re-expanded blastocysts showed higher in vitro hatching rates and total cell number calculated on the hatched blastocysts compared with slow re-expanded ones (P < 0.01). Peroxide status evaluation (P < 0.01) and TUNEL test (P < 0.05) revealed a higher number of positive cells in group B compared with group A. The quantitative analysis of protein synthesis revealed a higher synthesis in fast compared with slow re-expanded embryos (P < 0.05). Quantitative RT-PCR showed that 90-kDa Heat Shock Protein beta was more expressed in group A than in group B (P < 0.05), while the quantity of P34(cdc2), Cyclin b, Aquaporin 3, Na/K ATPase, and Actin did not differ between the two groups. Pregnancy rates after transfer to synchronized recipients were higher in fast compared to slow re-expanded blastocysts (P < 0.05). Our results evidenced that timing of blastocoelic cavity re-expansion after vitrification/warming and in vitro culture can be considered as a reliable index of in vitro produced embryo quality and developmental potential.
authors: Department of Physiological, Biochemical and Cellular Sciences, University of Sassari, Sassari, Italy. gioleoni@uniss.it
authors: G G
authors: GG
authors: Leoni
authors: F
authors: F
authors: Berlinguer
authors: S
authors: S
authors: Succu
authors: D
authors: D
authors: Bebbere
authors: F
authors: F
authors: Mossa
authors: M
authors: M
authors: Madeddu
authors: S
authors: S
authors: Ledda
authors: L
authors: L
authors: Bogliolo
authors: S
authors: S
authors: Naitana
mesh_terms: D000818:Animals; D001755:Blastocyst / Q000166:cytology* / Q000502:physiology*; D010064:Embryo Implantation / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro; D020287:In Situ Nick-End Labeling; D009865:Oocytes / Q000166:cytology* / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012756:Sheep
chemical_list: D012333:RNA, Messenger