Gómez Enrique, Rodríguez Aida, Muñoz Marta, Caamaño José Néstor, Carrocera Susana, Martín David, Facal Nieves, Díez Carmen
SERIDA, Somió, Gijón, Spain.
Reprod Fertil Dev. 2008;20(8):884-91. doi: 10.1071/rd08103.
Retinoids regulate development and differentiation of the bovine blastocyst in vitro, although the underlying mechanisms remain to be clarified. A challenge in reproductive biotechnology is the identification of pathways that regulate early embryonic development and their influence on blastocyst differentiation, apoptosis and survival to cryopreservation as traits of embryo quality. The present paper analyses the effects of short-term exposure (24 h) to retinoids on in vitro-produced bovine morulae. Immature cumulus oocyte complexes were in vitro matured and fertilised. Presumptive zygotes were subsequently cultured in modified synthetic oviduct fluid up to Day 6, in which morulae were randomly allocated to the different experimental groups. The treatments consisted of 0.1 microM LG100268 (LG; a retinoid X receptor agonist), 0.7 microM all-trans retinoic acid (ATRA; a retinoic acid receptor agonist) or no additives. Day 8 blastocyst development was increased in the ATRA-treated group compared with the LG and untreated embryos. In Day 7 embryos, the number of total cells and cells allocated to the trophectoderm were higher in the ATRA-treated group compared with untreated embryos. Apoptosis in the inner cell mass increased after LG treatment, whereas ATRA had no effect. After vitrification and warming, survival and hatching rates of Day 7 blastocysts did not change with retinoid treatment. Within the LG-treated and untreated blastocyst groups, survival and hatching rates were higher for Day 7 than Day 8 embryos; however, Day 8 blastocysts treated with ATRA showed improved hatching rates. In conclusion, treatment of morulae with ATRA in serum-free medium improves embryo development and quality without increasing the incidence of apoptosis and necrosis.
类视黄醇在体外调节牛囊胚的发育和分化，尽管其潜在机制仍有待阐明。生殖生物技术面临的一个挑战是确定调节早期胚胎发育的途径及其对囊胚分化、凋亡和冷冻保存存活率的影响，这些都是胚胎质量的特征。本文分析了短期（24小时）暴露于类视黄醇对体外生产的牛桑椹胚的影响。未成熟的卵丘卵母细胞复合体在体外成熟并受精。随后将推定的合子在改良的合成输卵管液中培养至第6天，其中桑椹胚被随机分配到不同的实验组。处理包括0.1微摩尔LG100268（LG；一种视黄酸X受体激动剂）、0.7微摩尔全反式视黄酸（ATRA；一种视黄酸受体激动剂）或不添加任何添加剂。与LG处理组和未处理的胚胎相比，ATRA处理组第8天的囊胚发育有所增加。在第7天的胚胎中，与未处理的胚胎相比，ATRA处理组的总细胞数和分配到滋养外胚层的细胞数更高。LG处理后内细胞团中的凋亡增加，而ATRA没有影响。玻璃化和复温后，第7天囊胚的存活率和孵化率不受类视黄醇处理的影响。在LG处理组和未处理的囊胚组中，第7天胚胎的存活率和孵化率高于第8天胚胎；然而，用ATRA处理的第8天囊胚的孵化率有所提高。总之，在无血清培养基中用ATRA处理桑椹胚可改善胚胎发育和质量，而不会增加凋亡和坏死的发生率。
