Nucleus transfer efficiency of ear fibroblast cells isolated from Bama miniature pigs at various ages.

Somatic cell nucleus transfer (SCNT) has been considered the most effective method for conserving endangered animals and expanding the quantity of adult animal models. Bama miniature pigs are genetically stable and share similar biological features to humans. These pigs have been used to establish animal models for human diseases, and for many other applications. However, there is a paucity of studies on the effect of ear fibroblasts derived from different age of adult Bama miniature pigs on nucleus transfer (NT). The present study examined the NT efficiency of ear fibroblasts from fetal, newborn, 1-, 2-, 4-, 6-, 12-month-old miniature pigs by using trypan blue staining, flow cytometry and NT technique, etc., and the cell biological function and SCNT efficiency were compared between groups. The results showed that ear fibroblasts grew well after passage in each group. Spindle-shaped cells initially predominated, and gradually declined with increase of culture time and replaced by polygonal cells. Irregular cell growth occurred in the 2-month-old group and the elder groups. The growth curves of the ear fibroblasts were "S-shaped" in different age groups. The cell proliferation of postnatal ear fibroblasts, especially those from 2-, 4-, 6-, 12-month-old miniature pigs was significantly different from that of fetus ear fibroblasts (P<0.05 or P<0.01). Two-month- and 4-month-old ear fibroblasts had a significantly higher proportion of G1 stage cells (85% to 91%) than those at 6 and 12 months (66% to 74%, P<0.01). The blastocyst rate of reconstructed embryos originating from newborn, 1-, 2-, 4-month-old donor pigs was 6.06% to 7.69% with no significant difference from that in fetus fibroblast group (8.06%). It was concluded that <4-month-old adult Bama miniature pigs represent a better donor cell resource than elder pigs.