Somatic cell nuclear transfer (SCNT) is a useful technology; however, its efficiency is low. In this study, we investigated the effects of cytoplasmic transfer into enucleated oocytes on the developmental competence and quality of cloned preimplantation bovine embryos via terminal deoxynucleotidyl transferase dUTP nick-end labeling, quantitative reverse transcription PCR, and immunocytochemistry. We used cytoplasm injection cloning technology (CICT), a new technique via which the cytoplasmic volume of an enucleated oocyte could be restored by injecting ∼30% of the cytoplasm of a donor oocyte. The percentages of embryos that underwent cleavage and formed a blastocyst were significantly higher (p < 0.05) in the CICT group than in the SCNT group (28.9 ± 0.8% vs. 20.2 ± 1.3%, respectively). Furthermore, the total cell number per day 8 blastocyst was significantly higher in the CICT group than in the SCNT group (176.2 ± 6.5 vs. 119.3 ± 7.7, p < 0.05). Moreover, CICT increased mitochondrial activity, as detected using MitoTracker® Green. The mRNA levels of DNA methyltransferase 1 and DNA methyltransferase 3a were significantly lower (p < 0.05) in the CICT group than in the SCNT group. The mRNA level of DNA methyltransferase 3b was lower in the CICT group than in the SCNT group; however, this difference was not significant (p > 0.05). Taken together, these data suggest that CICT improves the in vitro developmental competence and quality of cloned bovine embryos.

中文翻译：

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通过额外的辅助细胞质提高克隆的牛胚胎的体外发育能力和重编程效率。

体细胞核移植（SCNT）是一种有用的技术。但是，其效率低。在这项研究中，我们通过末端脱氧核苷酸转移酶dUTP缺口末端标记，定量逆转录PCR和免疫细胞化学研究了细胞质转移入去核卵母细胞对克隆的植入前牛胚胎发育能力和质量的影响。我们使用了细胞质注射克隆技术（CICT），这项新技术可以通过注入约30％的供体卵母细胞的细胞质来恢复去核卵母细胞的细胞质体积。CICT组中发生分裂并形成胚泡的胚胎百分比显着高于SCNT组（分别为28.9±0.8％和20.2±1.3％）（p <0.05）。此外，CICT组每天8个胚泡的总细胞数显着高于SCNT组（176.2±6.5对119.3±7.7，p <0.05）。此外，如使用MitoTracker®Green检测到的那样，CICT增强了线粒体活性。CICT组的DNA甲基转移酶1和DNA甲基转移酶3a的mRNA水平显着低于SCNT组（p <0.05）。CICT组的DNA甲基转移酶3b的mRNA水平低于SCNT组。但是，这种差异并不显着（p> 0.05）。综上所述，这些数据表明，CICT可提高克隆的牛胚胎的体外发育能力和质量。使用MitoTracker®Green检测到。CICT组的DNA甲基转移酶1和DNA甲基转移酶3a的mRNA水平显着低于SCNT组（p <0.05）。CICT组的DNA甲基转移酶3b的mRNA水平低于SCNT组。但是，这种差异并不显着（p> 0.05）。综上所述，这些数据表明，CICT可提高克隆的牛胚胎的体外发育能力和质量。使用MitoTracker®Green检测到。CICT组的DNA甲基转移酶1和DNA甲基转移酶3a的mRNA水平显着低于SCNT组（p <0.05）。CICT组的DNA甲基转移酶3b的mRNA水平低于SCNT组。但是，这种差异并不显着（p> 0.05）。综上所述，这些数据表明，CICT可提高克隆的牛胚胎的体外发育能力和质量。