98 BLASTOCYST DEVELOPMENT RATE OF CLONED CAT EMBRYOS USING SERIAL CLONING

Abstract

Domestic cats are a useful research model to develop assisted reproductive technologies for the conservation of endangered felids. Previously, we produced cloned offspring derived from somatic cell nuclear transfer of ear skin fibroblasts obtained from a deaf, odd-eyed, male Turkish Angora. The aim of this study was to assess the cloning efficiency of the fibroblasts derived from a cloned cat. Fibroblast cell lines were established from 6-mm skin biopsies taken from a deaf, odd-eyed, male Turkish Angora and his clone. The protocol for nuclear transfer was described previously (Yin et al. 2005 Reproduction 129, 245–249). Briefly, cumulus cells were removed from the ova by gently pipetting them into TCM-199 supplemented with 0.1% hyaluronidase. The denuded oocytes were then cultured in TCM-199 supplemented with 0.2 µg mL^-1 demecolcine for 1 h and placed into TCM-199 containing 5 µg mL^-1 cytochalasin B and 0.2 µg mL^-1 demecolcine. The first polar body and protruded chromatin plate were removed with a beveled micropipette. Micromanipulation was used to place a single donor cell nucleus into the perivitelline space of enucleated ova. The ovum-cell couplets were fused and pulse activated. The activated couplets were cultured in 500 µL of CRI medium supplemented with 0.3% BSA for 2 days. The cleaved embryos were cultured in CRII medium supplemented with 10% FBS for 5 days. The cleavage and blastocyst development rates were 38.5% and 3.5% for second generation cloned embryos. A total of 310 second generation cloned embryos were transplanted to 9 surrogates, and 2 pregnancies at 30 days were determined by ultrasonography. One pregnancy was aborted at 40 days of gestation; the second pregnancy continued. These results indicate that the serial cloning of a cat can be generated efficiently up until pregnancy.

This work was supported by KOSEF (grant #M10525010001-05N2501-00110).