TY - JOUR
T1 - Effects of long-term treatment with estrogen and medroxyprogesterone acetate on synapse number in the medial prefrontal cortex of aged female rats
AU - Chisholm, Nioka C.
AU - Juraska, Janice M.
PY - 2012/7
Y1 - 2012/7
N2 - Objective: The present study investigated the effects of long-term hormone treatment, including the most commonly prescribed progestin, medroxyprogesterone acetate, during aging on synaptophysin-labeled boutons, a marker of synapses, in the medial prefrontal cortex (mPFC) of rats. Methods: Female Long Evans hooded rats were ovariectomized at middle age (12-13 mo) and were placed in one of four groups: no replacement (n = 5), 17β-estradiol alone (n = 6), estradiol and progesterone (n = 7), or estradiol and medroxyprogesterone acetate (n = 4). Estradiol was administered in the drinking water and progestogens were administered via subcutaneous pellets that were replaced every 90 days. After 7 months of hormone replacement, the animals were euthanized, and the brains were stained for synaptophysin, a membrane component of synaptic vesicles. The density of synaptophysin-labeled boutons was quantified in the mPFC using unbiased stereology and multiplied by the volume of the mPFC to obtain the total number. Results: Animals receiving estradiol and medroxyprogesterone acetate had significantly more synaptophysin-labeled boutons in the mPFC than did animals not receiving replacement (P < 0.03) and those receiving estradiol and progesterone (P < 0.02). In addition, there was a nonsignificant trend for animals receiving estradiol alone to have more synapses than those receiving estradiol and progesterone. Conclusions: This study is the first to examine the effects of estradiol and medroxyprogesterone acetate during rat aging on cortical synaptic number. Estradiol with medroxyprogesterone acetate, but not progesterone, resulted in a greater number of synapses in the mPFC during aging than did no replacement.
AB - Objective: The present study investigated the effects of long-term hormone treatment, including the most commonly prescribed progestin, medroxyprogesterone acetate, during aging on synaptophysin-labeled boutons, a marker of synapses, in the medial prefrontal cortex (mPFC) of rats. Methods: Female Long Evans hooded rats were ovariectomized at middle age (12-13 mo) and were placed in one of four groups: no replacement (n = 5), 17β-estradiol alone (n = 6), estradiol and progesterone (n = 7), or estradiol and medroxyprogesterone acetate (n = 4). Estradiol was administered in the drinking water and progestogens were administered via subcutaneous pellets that were replaced every 90 days. After 7 months of hormone replacement, the animals were euthanized, and the brains were stained for synaptophysin, a membrane component of synaptic vesicles. The density of synaptophysin-labeled boutons was quantified in the mPFC using unbiased stereology and multiplied by the volume of the mPFC to obtain the total number. Results: Animals receiving estradiol and medroxyprogesterone acetate had significantly more synaptophysin-labeled boutons in the mPFC than did animals not receiving replacement (P < 0.03) and those receiving estradiol and progesterone (P < 0.02). In addition, there was a nonsignificant trend for animals receiving estradiol alone to have more synapses than those receiving estradiol and progesterone. Conclusions: This study is the first to examine the effects of estradiol and medroxyprogesterone acetate during rat aging on cortical synaptic number. Estradiol with medroxyprogesterone acetate, but not progesterone, resulted in a greater number of synapses in the mPFC during aging than did no replacement.
KW - Estrogen
KW - Hormone therapy
KW - MPA
KW - Progesterone
KW - Synaptophysin
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U2 - 10.1097/gme.0b013e31824d1fc4
DO - 10.1097/gme.0b013e31824d1fc4
M3 - Article
C2 - 22617337
AN - SCOPUS:84863533768
SN - 1072-3714
VL - 19
SP - 804
EP - 811
JO - Menopause
JF - Menopause
IS - 7
ER -