Animal Science Papers and Reports

Analysis of in vivo- and in vitro-derived pig expanded blastocysts based on DNA fragmentation*

Magdalena Bry³a**, Monika Trzciٌska, Jaros³aw Wieczorek

Abstarc :

The aim of the study was to investigate the competence of in vivo- and in vitro-derived pig  expanded blastocysts by analysing DNA fragmentation using TUNEL. A total of 533 porcine expanded blastocysts were examined, and results were evaluated using Fisher’s test. Significant differences in the incidence of fragmented nuclei (detected by the TUNEL reaction) and all nuclei (detected by DAPI) were identified between in vivo- and in vitro-derived embryos at the expanded blastocyst stage. The total numbers of nuclei observed in in vivo-derived embryos were significantly different from those in in vitro-cultured embryos (89.1±13.4 and 47.7±25.1, respectively). TUNEL index in in vitro-cultured embryos (28.3%) was significantly higher (P<0.01) than in in vivo-derived blastocysts (4%). These findings indicate that in vivo- and in vitro-derived expanded blastocysts consisting of a small number of cells are characterized by a high incidence of DNA fragmentation. The total number of nuclei in in vivo- and in vitro-derived blastocysts correlated negatively with the number of TUNEL-positive nuclei (r = -0.51; P<0.0001) and the TUNEL index (r = -0.69; P<0.0001), whereas the number of TUNEL-positive nuclei was positively correlated with the TUNEL index (r = 0.95; P<0.0001). Moreover, significant differences were observed between embryos collected from
individual experiments.

Key Word :
blastocysts / DNA fragmentation / in vitro / in vivo / porcine expanded blastocysts / TUNEL

Volume 27, Number 1, - 2009