a1 Institute for Cattle Breeding Ltd Rapotin, Vyzkumniku 267, 788 13 Vikyrovice, Czech Republic
a2 Institute for Cattle Breeding Ltd Rapotin, Vyzkumniku 267, 788 13 Vikyrovice, Czech Republic
a3 AgriResearch Rapotin Ltd, Vyzkumniku 267, 788 13 Vikyrovice, Czech Republic
The goal of this study was to examine the effect of insulin-like growth factor I (IGF-I; added during post-thaw culture (48 h)) on the preimplantation viability and quality of cryopreserved bovine in vivo recovered embryos. The morula stage embryos, non-surgically recovered from superovulated dairy cows of Czech Fleckvieh cattle breed, had previously been cryopreserved by a slow freezing technique and stored in liquid nitrogen since 1989–1990. Following thawing, the embryos were cultured for 48 h either alone (no IGF-I) or in the presence of IGF-I (10 or 100 ng/ml); non-cultured embryos served as a control. Thereafter, the embryos were analyzed for cleavage to the blastocyst stage, apoptosis (TUNEL), embryo cell number and quality of actin cytoskeleton. Following post-thaw culture 41% of embryos developed to advanced blastocysts. IGF-I increased this per cent and, at a higher dose, essentially reduced the per cent of degenerated embryos. In cultured embryos, IGF-I at both doses elevated the cell number compared with non-cultured embryos. However, in comparison with embryos cultured without IGF-I, only the higher IGF-I dose resulted in elevating the embryo cell number. The TUNEL index was significantly lowered by IGF-I treatment. Thawed embryos were mostly of the grade III actin type and fewer (12%) had grade II actin, whilst no grade I actin embryos were noted. The addition of IGF-I resulted in the appearance of grade I actin embryos (8.33 and 6.9% for 10 and 100 ng/ml, respectively). These observations indicate that the addition of IGF-I during post-thaw culture can improve the quality of bovine cryopreserved embryos.
(Received July 05 2010)
(Accepted September 29 2010)
(Online publication February 08 2011)
c1 All correspondence to: Alexander V. Makarevich. Institute for Cattle Breeding Ltd Rapotin, Vyzkumniku 267, 788 13 Vikyrovice, Czech Republic. Tel.: +421 37 6546 334. Fax: +421 37 6546 480. e-mail: firstname.lastname@example.org