70 NON-PLATED GRANULOSA AND CUMULUS CELLS AND FIRST PASSAGE FIBROBLASTS AS NUCLEUS DONOR FOR GOAT CLONING

Abstract

Different types of somatic cells have been used as nucleus donors for cloning. Most of them were previously cultured in vitro as a monolayer through several plate passages. The experiment reported here was conducted to study the potential usages of granulosa and cumulus cells for cloning without previous culture as a monolayer. A first-plate-passage fibroblast was also used. Oocytes were aspirated by laparoscopy from Criolla goats and matured in TCM-199 + 5% FCS at 39°C for 24 h. Matured oocytes were denuded by vortexing for 3 min in TL HEPES with 1 mg/mL bovine testis hyaluronidase. Metaphases were assessed and oocytes were enucleated by visualization with Hoechst 33342 (5 μg/mL) under UV light (<6 s). Granulosa and cumulus cells were also recovered by laparoscopy and maintained in maturation medium in cryotube for 20 h at room temperature or 39°C, respectively. Goat adult ear fibroblasts were cultured for 1 or 2 weeks and used 2 days after confluence. All types of donor cells were transferred to the perivitlline space of enucleated oocytes and fused by an electrical pulse. After 2 h, activation was induced by incubation in TL-HEPES with 5 µM ionomycin for 4 min and 2 mM 6-DMAP for 3 h. The oocytes were then washed with TL-HEPES and cultured in SOF medium and atmosphere of 5% CO₂ + 5% O₂ + 90% N₂. Cleavage (Day 2) and development to blastocysts (Day 6) were recorded and analyzed by chi-square test. The cleavage rate for non-plated granulosa cells was higher than for the other treatment goups; cumulus cells had a lower rate of development to blastocysts (Table 1). These results suggest that granulosa cells collected and maintained for 24 h at room temperature could be used to produce cloned blastocysts.

Table 1. Effect of non-plated granulosa and cumulus cells and first passage fibroblasts as donor nucleus oocytes in goat cloning