It has been well recognized that oocyte quality declines in aging animals. However, to date, the underlying mechanism remains to be explored. In the present study, we report that oocytes and embryos from aged mice (42-45 weeks old) display the reduced expression of SIRT6 protein, accompanying with telomere shortening and DNA lesions. Moreover, we demonstrate that specific depletion of SIRT6 in oocytes induces dysfunctional telomeres and apoptosis of the resultant early embryos, leading to the developmental delay and cytoplasmic fragmentation. Importantly, we further find that overexpression of SIRT6 in aged oocytes promotes the telomere elongation in 2-cell embryos and lowers the incidence of apoptotic blastomeres. In summary, our data indicate a role for SIRT6 in modulating telomere function during oocyte maturation and embryonic development, and discover that SIRT6 reduction is an important point connecting maternal aging and quality control of oocyte/embryos.
Keywords: aging; embryo development; oocyte quality; sirtuin; telomere.