Fetal bovine serum (FBS) supplementation has beneficial effects on in vitro porcine embryonic development, but the underlying mechanisms are unclear. In the present study we found that the addition of FBS to PZM-3 increased the number of cells in porcine blastocysts and hatching rate in vitro primarily by promoting proliferation of the inner cell mass and further differentiation. Moreover, based on the following results, we surmise that FBS benefits blastocyst development by activating Rho-associated kinase (ROCK) signalling: (1) the ROCK signalling inhibitor Y-27632 decreased the blastocyst rate and the number of cells in blastocysts, whereas FBS rescued the developmental failure induced by Y-27632; (2) the mRNA levels of two ROCK isoforms, ROCK1 and ROCK2, were significantly increased in blastocysts derived from medium containing FBS; and (3) FBS increased RhoA/Rho-kinase expression in the nucleus of embryonic cells. These results indicate that FBS promotes the in vitro development of porcine embryos by activating ROCK signalling in a chemically defined medium.

胎牛血清（FBS）补充剂对体外猪胚胎发育具有有益作用，但其潜在机制尚不清楚。在本研究中，我们发现，加入FBS，以PZM-3增加在猪囊胚细胞和孵化率的数量在体外主要通过促进内细胞团，并进一步分化的增殖。此外，基于以下结果，我们推测FBS通过激活Rho相关激酶（ROCK）信号传导而有利于胚泡发育：（1）ROCK信号抑制剂Y-27632降低了胚泡率和囊胚中的细胞数量，而FBS挽救了由Y-27632引起的发育失败；（2）两种ROCK亚型ROCK1和ROCK2在含有FBS的胚泡中显着增加。（3）FBS增加了胚胎细胞核中RhoA / Rho激酶的表达。这些结果表明，FBS通过在化学成分确定的培养基中激活ROCK信号传导来促进猪胚胎的体外发育。