Age-related changes of the hippocampal estrogen receptor gene expression in senescence-accelerated mouse

Abstract

Estrogen receptor (ER) has two subtypes, ERα and ERβ. In this study, age-related changes of hippocampal gene expressions of ERα and ERβ were examined in senescence-accelerated mouse (SAM) with real-time reverse transcription-polymerase chain reaction (RT-PCR) technique, in an attempt to explore the relationship between estrogen receptor expression and age-related deficit of learning and memory in SAM. The results showed that the hippocampal ERα gene expressed constantly at the ages from 3 to 15 months in both SAMR1 and SAMP8. But the change of hippocampal ERβ gene expression was different from ERα gene during the aging process. In SAMR1, the expression of ERβ gene kept at a relatively high level at the ages from 3 to 12 months, and decreased significantly at the age of 15 months. In SAMP8, the expression of ERβ gene kept at a higher level at the ages of 3 and 6 months, and gradually decreased with advancing age, and reached the lowest level at the age of 15 months in both genders. The expression of ERβ gene decreased earlier in SAMP8 compared with SAMR1 during the aging process. These results suggested that the early decline of the expression of ERβ gene, but not ERα gene in the hippocampus of SAMP8 contribute to their age-related deterioration of learning and memory function.