Effect of follistatin on pre‐implantational development of pig parthenogenetic embryos

Abstract

The present study was designed to explore effects of follistatin (FST) on pre-implantational development of parthenogenetically activated embryos (PAEs) in pigs. First, we investigated the FST messenger RNA expression level and dynamic FST protein expression patterns in porcine oocytes and PAEs. Then, PAEs were placed in embryo culture medium supplemented with 10 ng/mL of FST-288, FST-300, and FST-315. Next, PAEs were cultured with 0, 1, 10 and 100 ng/mL of FST-315 protein throughout the in vitro culture (IVC) duration. Further, 10 ng/mL of FST-300 was added from the start of IVC in which PAEs were treated for 30, 48 and 60 h. The results showed that 1 ng/mL FST-315 could significantly increase the total cell numbers of blastocyst and trophectoderm cell number in PAEs. Exogenous FST-300 supplementation could significantly promote the early cleavage divisions and improve the blastocyst formation rate of porcine embryos. FST-300 appeared to affect early embryonic development before activation of the embryonic genome. In all, the study confirmed for the first time that FST plays a role in promoting early embryonic development in pigs, which differed with different FST subtypes. FST-300 could facilitate the initial cleavage time and improve the blastocyst formation rate, and FST-315 could improve the blastocyst quality.

Follistatin (FST) is expressed in buffalo (Bubalus bubalis) ovarian follicles and promotes oocyte maturation and early embryonic development

“…This results of our study in buffalo are inconsistent with previous studies (Li et al, 2018), which differences between species might have caused. FST was detected only in healthy follicles, suggesting its important role in the maturation of dominant follicles.…”

“…With the development of follicles, the expression level of FST gradually increased, and some studies found that FST only existed in healthy follicles (Xu et al., 2014). This results of our study in buffalo are inconsistent with previous studies (Li et al., 2018), which differences between species might have caused. FST was detected only in healthy follicles, suggesting its important role in the maturation of dominant follicles.…”

“…This suggests that FST could have a significant role in IVM and the regulation of oocyte maturation. This result is not consistent with the results of FST in rhesus monkeys (Vandevoort et al, 2009) and swine (Li et al, 2018) but consistent with previous findings that FST expression gradually increases during follicular development (Xu et al, 2014). It is speculated that the differences in species might be the cause of this phenomenon.…”

“…Studies have found that FST can inhibit the function of FSH (Bilezikjian et al., 1998), and further study has gradually discovered its biological function in reproduction (Knight & Glister, 2001). FST has been documented to improve the in vitro development efficiency and blastocyst formation rate of early embryos in rhesus monkeys (Vandevoort et al., 2009), cattle (Kyung‐Bon et al., 2009), and pigs (Li et al., 2018). FST regulates the proliferation and apoptosis of granulosa cells by acting on the ovary through paracrine mode (Woodruff et al., 1990).…”

“…Patel et al found that FST gene expression in high-quality oocytes was much higher than in low-quality oocytes (Patel et al, 2007). FST improved in vitro development efficiency and early embryo blastocyst formation rates in the rhesus monkey (Vandevoort et al, 2009), bovine (Kyung-Bon et al, 2009), and swine (Li et al, 2018). All these indicated that FST might regulate oocyte maturation in various ways.…”