Oocyte Age-Dependent DNA Damage Can Be Reverted By The DNA Repair Competent Karyoplasm Of Young Oocytes
For a long time, it was believed that as female mammals age, their egg cells accumulate DNA damage that is irreversible, leading to reduced fertility and a higher chance of chromosomal abnormalities in offspring. This understanding has shaped how we view reproductive aging, suggesting an inevitable decline in egg quality. However, recent research challenges this long-held assumption. Scientists conducted experiments where they took the nucleus, which contains the genetic material, from older egg cells and transferred it into the main body (cytoplasm) of younger egg cells, after removing the young egg cell’s own nucleus. They found that this process dramatically suppressed the signs of age-dependent DNA damage in the older egg cells. Not only did the DNA damage decrease, but the way the genetic material was organized within the cell also partially recovered, and surprisingly, the chromosomes separated more accurately during cell division. The key to this repair ability was found to be specific factors within the young egg cell’s nucleus that are not bound to the chromosomes. Ultimately, these “repaired” egg cells showed an improved ability to develop into full-term embryos. These findings suggest that the age-associated decline in egg quality might not be a one-way street and could potentially be mitigated, opening up exciting new possibilities for future cell-based therapies to address age-related infertility.
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