Trx及其抑制因子TXNIP基因在发育不同阶段牛体外胚胎中的转录与表达

Transcriptional expression of Trx and its inhibitor TXNIP genes during different developmental stages of bovine embryos produced in vitro

【目的】研究Trx及其抑制因子TXNIP基因在牛卵母细胞及不同发育阶段体外受精胚胎中的表达变化.【方法】采用实时荧光定量PCR方法,检测牛GV期卵母细胞、MⅡ期卵母细胞、受精卵、2-4细胞胚胎、8-16细胞胚胎、桑椹胚和囊胚中Trx1、Trx2和TXNIP基因mRNA的相对表达量.【结果】Trx1和Trx2基因在GV期卵母细胞和不同发育阶段的胚胎均有不同程度的表达.GV期卵母细胞Trx1mRNA表达量最高,随着卵母细胞的成熟及受精后胚胎的发育逐渐降低,囊胚期胚胎表达量又急速升高.Trx2基因在受精前的卵母细胞中高表达,受精后表达量逐渐下降,囊胚期胚胎Trx2 mRNA的表达量最低.内源性抑制因子TXNIP基因在2-4细胞胚胎阶段之前都是高表达,从8-16细胞胚胎阶段表达下降,在囊胚期胚胎表达量最低.【结论】牛卵母细胞及附植前胚胎自身的抗氧化能力在发育的不同阶段可能有所不同,而Trx1、Trx2及TXNIP基因在卵母细胞和不同发育阶段胚胎中的表达模式可能起到了重要的调控作用.

[Objective] To study the changes of expression of Trx and TXNIP in oocytes and in vitro- fertilized （IVF） bovine pre-implantation embryos. [Method] The expression patterns of Trxl , Trx2 and TXNIP genes during the oocyte maturation and embryonic development in bovine embryos at different de- velopmental stages were analyzed using fluorescent real-time PCR assay. [Result]Trxl and Trx2 genes were present from GV oocytes to blastocyst stage embryos. The highest expression of Trxl mRNA was de- tected in GV oocytes. With the oocyte maturation and embryo development after fertilization, the rrxl transcript was gradually decreased, while in the blastocyst stage, the Trxl mRNA expression level was rap-idly increased. The Trx2 transcript was maintained a high level before fertilization, then gradually de- creased and the lowest expression was observed at the blastocyst stage. The transcript of TXNIP,a nega- tive regulator of Trx,was abundantly expressed before the 2-4 cell stage, and then decreased significantly following 8--16 cell stage, and the lowest expression level was found in the blastocyst stage. [Conclusion] The antioxidant capacities of bovine oocytes and preimplantation embryos vary at different developmental stages, and the expression patterns of Trxl, Trz2 and TXNIP genes might play pivotal roles in regulating this process.