Knockdown of p66Shc by siRNA injection rescues arsenite-induced developmental retardation in mouse preimplantation embryos

•Microinjection of p66Shc siRNA into the pronucleus of zygote results in the knowdown of p66Shc.•Knockdown of p66shc improves the developmental competence of arsenite-exposed embryos in vitro.•P66Shc is a key factor linking oxidative stress with arsenite-induced developmental retardation.•Our findings provide new insights into the possible clinical intervention in the embryos in the future.•Single-embryo expression analysis provides a novel tool to investigate early embryos.

Two-cell arrest plays a principal role in the elevated levels of embryo loss during the first week of development in mouse. Previously, we have shown that arsenic can apparently induce 2-cell arrest in mouse preimplantation embryo and the expression of oxidative stress adaptor protein p66Shc is up-regulated in this process. In the present study, we demonstrated that microinjection of p66Shc siRNA into the pronucleus of zygotes resulted in a markedly decrease in both mRNA and protein levels of p66Shc. The arsenite-induced 2-cell arrests, along with a reduction in the levels of reactive oxygen species (ROS), were significantly inhibited and the number of embryos developing to morula stage concurrently increased upon p66shc siRNA microinjection. These findings indicate that knockdown of p66shc improves the developmental competence of arsenite-exposed embryos in vitro by increasing the resistance to oxidative stress. In addition, we highlight the utility of single-embryo analysis in preimplantation embryos.