338 INFLUENCE OF OOCYTE DIAMETER AND MORPHOLOGY ON APOPTOSIS AND BLASTOCYST DEVELOPMENT IN PREPUBERTAL GOAT
B. Anguita A , M. T. Paramio A , A. R. Jimenez-Macedo A , R. Romaguera A , R. Morato A , T. Mogas A and D. Izquierdo AAFacultat de Veterinaria, Universitat Autonoma de Barcelona, Bellaterra, Barcelona, Spain
Reproduction, Fertility and Development 19(1) 284-285 https://doi.org/10.1071/RDv19n1Ab338
Submitted: 12 October 2006 Accepted: 12 October 2006 Published: 12 December 2006
Abstract
In vitro embryo production from prepubertal females is lower than from adult females. There are different hypotheses to explain this fact. The aim of this study was to analyze the apoptosis of prepubertal goat oocytes and its relationship to embryo development according to oocyte diameters. Oocytes from slaughtered prepubertal goats were recovered by slicing, and classified as: healthy (H: compact cumulus cells and homogeneous cytoplasm) and early atresic (EA: granulated cytoplasm and/or initial cumulus expansion), and by oocyte diameter: 110–125 µm, 125–135 µm, and >135 µm. They were matured in TCM-199 for 27 h at 38.5°C and 5% CO2 in air. After maturation, a sample of oocytes was denuded, and oocytes and cumulus cells, separately, were analyzed by TUNEL assay (In Situ Cell Death Detection Kit; Roche Diagnostics SL, Barcelona, Spain) to study the apoptosis. The rest of oocytes were fertilized in vitro and the presumptive zygotes were cultured for 8 days in SOF at 38.5°C, 5% CO2 and 90% N2. Results are shown in Table 1. Fisher's exact test showed a significantly higher percentage of blastocyst formation in the largest oocytes than in those with smaller diameters; moreover, the largest healthy oocytes produced a higher rate of blastocyst formation than the early atretic oocytes of the same diameter group. TUNEL assay showed that the percentage of apoptotic oocytes was lower in the largest healthy oocytes, whereas in early atresic oocytes, apoptosis was not related to oocyte size. After maturation, the percentage of apoptotic cumulus cells was low (10% of cells) in all oocyte categories. However, in the early atretic group, the percentage of apoptotic cumulus cells increased in oocytes < 125 µm. In conclusion, in prepubertal goat oocytes, the percentage of blastocysts formed depends on oocyte diameter and the percentage of apoptotic cumulus cells.
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This work was supported by a grant from Generalitat de Catalunya (2006FIC 00187) and a grant from the Universitat Autonoma de Barcelona (EME-2004-25).
