Examination of CA1 hippocampal DNA methylation as a mechanism for closing of estrogen’s critical window

The study presents several novel findings that relate to the idea that alterations in DNA methylation occurs during aging and may be linked to senescent physiology, including a decline in circulating E2. In addition, the evidence has been provided that DNA methylation contributes to the closing of the critical window for E2 effects on synaptic function. The study was conducted on fisher 344 female rats of three different age groups, young (5-6 months, n= 10), middle-age 6-12 months, n= 10) and aged (12-18months, n= 11). Animals were ovariectomized and after 6 weeks injection of estrogen and oil treatmentwere conducted for two consecutive days 24 hours apart. After 6 hours of last injection, CA1 region of brain were collected and stored in -80ᵒC. Genomic DNA was isolated to conduct whole genome bisulfite sequencing to investigate the effect of age and estrogen treatment on the DNA methylome of the CA1 region.