Federal University of Juiz de Fora, Juiz de Fora, MG 36036-900, Brazil ; Embrapa Dairy Cattle Research Center, Juiz de Fora, MG 36038-330, Brazil.
Federal University of Juiz de Fora, Juiz de Fora, MG 36036-900, Brazil.
J Anim Sci Biotechnol. 2014 Jun 10;5(1):33. doi: 10.1186/2049-1891-5-33. eCollection 2014.
Due to high neutral lipids accumulation in the cytoplasm, in vitro-produced embryos from Bos primigenius indicus and their crosses are more sensitive to chilling and cryopreservation than those from Bos primigenius taurus. The objective of the present study was to evaluate the effects of trans-10, cis-12 conjugated linoleic acid (CLA) on the development and cryotolerance of crossbred Bos primigenius taurus x Bos primigenius indicus embryos produced in vitro, and cultured in the presence of fetal calf serum. Bovine zygotes (n = 1,692) were randomly assigned to one of the following treatment groups: 1) Control, zygotes cultured in Charles Rosenkrans 2 amino acid (CR2aa) medium (n = 815) or 2) CLA, zygotes cultured in CR2aa medium supplemented with 100 μmol/L of trans-10, cis-12 CLA (n = 877). Embryo development (cleavage and blastocyst rates evaluated at days 3 and 8 of culture, respectively), lipid content at morula stage (day 5) and blastocyst cryotolerance (re-expansion and hatching rates, evaluated 24 and 72 h post-thawing, respectively) were compared between groups. Additionally, selected mRNA transcripts were measured by Real-Time PCR in blastocyst stage.
The CLA treatment had no effect on cleavage and blastocyst rates, or on mRNA levels for genes related to cellular stress and apoptosis. On the other hand, abundance of mRNA for the 1-acylglycerol-3-phosphate 0-acyltransferase-encoding gene (AGPAT), which is involved in triglycerides synthesis, and consequently neutral lipid content, were reduced by CLA treatment. A significant increase was observed in the re-expansion rate of embryos cultured with trans-10, cis-12 CLA when compared to control (56.3 vs. 34.4%, respectively, P = 0.002). However, this difference was not observed in the hatching rate (16.5 vs. 14.0%, respectively, P = 0.62).
The supplementation with trans-10, cis-12 CLA isomer in culture medium reduced the lipid content of in vitro produced bovine embryos by reducing the gene expression of 1-acylglycerol 3-phosphate 0-acyltransferase (AGPAT) enzyme. However, a possible improvement in embryo cryotolerance in response to CLA, as suggested by increased blastocyst re-expansion rate, was not confirmed by hatching rates.
由于细胞质中中性脂肪的积累较高，与来自普通牛的胚胎相比，来自大额牛及其杂交种的体外生产胚胎对冷刺激和冷冻保存更为敏感。本研究的目的是评估反式-10，顺式-12 共轭亚油酸（CLA）对体外生产的杂交大额牛 x 普通牛胚胎的发育和冷冻耐受性的影响，并在胎牛血清存在下进行培养。将牛受精卵（n=1692）随机分配到以下处理组之一：1）对照组，在查尔斯罗森克兰斯 2 氨基酸（CR2aa）培养基中培养的受精卵（n=815）或 2）CLA 组，在 CR2aa 培养基中添加 100μmol/L 反式-10，顺式-12 CLA 的受精卵（n=877）。分别在培养的第 3 天和第 8 天评估胚胎发育（卵裂和囊胚率）、桑椹胚期的脂质含量（第 5 天）和囊胚冷冻耐受性（解冻后 24 小时和 72 小时的再扩张和孵化率），并在各组之间进行比较。此外，在囊胚阶段通过实时 PCR 测量选定的 mRNA 转录本。
CLA 处理对卵裂和囊胚率或与细胞应激和细胞凋亡相关的基因的 mRNA 水平没有影响。另一方面，参与甘油三酯合成的 1-酰基甘油-3-磷酸 0-酰基转移酶编码基因（AGPAT）的 mRNA 丰度降低，这与中性脂质含量降低有关。与对照组相比，用反式-10，顺式-12 CLA 培养的胚胎的再扩张率显著增加（分别为 56.3%和 34.4%，P=0.002）。然而，在孵化率方面并未观察到这种差异（分别为 16.5%和 14.0%，P=0.62）。
在培养基中添加反式-10，顺式-12 CLA 异构体可通过降低 1-酰基甘油 3-磷酸 0-酰基转移酶（AGPAT）酶的基因表达来降低体外生产的牛胚胎的脂质含量。然而，CLA 对胚胎冷冻耐受性的改善可能并未得到孵化率的证实，因为囊胚的再扩张率有所增加。
