Interleukin-6 and its receptor in the development of in vitro fertilized ovine embryos

To study the effects of interleukin-6 (IL-6) and its receptor (IL-6R) at each stage in the early development of in vitro-fertilized (IVF) sheep embryos, the mRNA and protein expression levels of IL-6 and IL-6R were evaluated along with their localization, through real-time PCR, protein blotting, and immunohistochemistry. Specific patterns of IL-6 and IL-6R expression were recorded at both the mRNA and protein level at each stage of early ovine embryonic development. IL-6 was distributed primarily on the cytoplasm, however IL-6R was concentrated much more on the cell membrane. The role of IL-6 and IL-6R in the early ovine embryonic development was studied via the in vitro addition of recombinant human IL- 6, at different concentrations and RNA interference. The addition of the recombinant IL-6 increased the embryonic IL-6 mRNA level, and the addition of 10 ng/mL IL-6 significantly increased the embryo cleavage rate (p < 0.05). IL-6 RNA interference effectively reduced the IL-6 protein level, but did not affect the rate of development of the IVF ovine embryos. This study provides a practical basis for further indepth studies on the mechanisms involved during early ovine embryonic development.