Vitrification of farmed blue fox oocytes in ethylene glycol and DMSO-based solutions using open-pulled straw (OPS).

Farmed blue fox was used as a model to develop cryopreservation protocol for nondomestic canine species. We report here the developmental potential of farmed blue fox oocytes after vitrification with a two-step OPS method. Oocytes were collected and pre-cultured for 0, 24, 48, 72 hours respectively before cryopreservation. Vitrification of oocytes was achieved by a 30 sec treatment in 10% ethylene glycol (EG) or 10% EG + 10% dimethyl sulfoxide (DMSO) at 25 degree C followed by a 25 sec equilibration in EFS30 (30% (v/v) EG +21% (w/v) Ficoll +0.35M sucrose) or EDFS30 (15% (v/v) EG +15% (v/v) DMSO +21% (w/v) Ficoll +0.35M sucrose), before plunging into liquid nitrogen. The survival of oocytes after vitrification was assessed morphologically immediately after warming, and cultured for in vitro maturation. For comparison, control oocytes were cultured for in vitro maturation for 96 hours. The best result was obtained when oocytes were pre-cultured for 72 hours, first exposed to 10 percent EG + 10% DMSO and vitrified in EDFS30. The survival percentage of oocytes under these conditions was not significantly different (P > 0.05) from that of the control.

Surgical embryo transfer resulted in birth of live offspring in farmed blue fox.

Finland blue fox (Alopex lagopus) has great reputation in pelt industry around the world for its large size and top-ranking fur quality; however, both the herd size and the average survival rate of purebred offspring are rather low in production systems in China. Surgical transfer of blue fox embryos was investigated as a means to increase the population fox and also as a possible means to conserve endangered canine species. The animals were chosen on the basis of synchrony in natural oestrus. During the reproductive season of blue fox, 59 embryos were flushed from 6 farmed donors 9-11 days after the first insemination, and 53 embryos were transferred surgically into the uteri of the 6 paired recipients with natural synchronized oestrous. Two of the recipients littered 46-49 days after embryo transfer; one gave birth to 7 pups and the other 1 pup. This report describes the first successful embryo transfer in the farmed blue fox in China.

Transcriptome profiling of human oocytes experiencing recurrent total fertilization failure.

There exist some patients who face recurrent total fertilization failure during assisted reproduction treatment, but the pathological mechanism underlying is elusive. Here, by using sc-RNA-seq method, the transcriptome profiles of ten abnormally fertilized zygotes were assessed, including five zygotes from one patient with recurrent Poly-PN zygotes, and five zygotes from a patient with pronuclear fusion failure. Four zygotes with three pronuclear (Tri-PN) were collected from four different patients as controls. After that, we identified 951 and 1697 significantly differentially expressed genes (SDEGs) in Poly-PN and PN arrest zygotes, respectively as compared with the control group. KEGG analyses indicated down regulated genes in the Poly-PN group included oocyte meiosis related genes, such as PPP2R1B, YWHAZ, MAD2L1, SPDYC, SKP1 and CDC27, together with genes associated with RNA processing, such as SF3B1, LOC645691, MAGOHB, PHF5A, PRPF18, DDX5, THOC1 and BAT1. In contrast, down regulated genes in the PN arrest group, included cell cycle genes, such as E2F4, DBF4, YWHAB, SKP2, CDC23, SMC3, CDC25A, CCND3, BUB1B, MDM2, CCNA2 and CDC7, together with homologous recombination related genes, such as NBN, XRCC3, SHFM1, RAD54B and RAD51. Thus, our work provides a better understanding of transcriptome profiles underlying RTFF, although it based on a limited number of patients.