Effects of 17 beta-estradiol replacement on the apoptotic effects caused by ovariectomy in the rat hippocampus

Autor(es)

Sales, Sayuri ^[1] ; Ureshino, Rodrigo Portes ^[2] ; dos Santos Pereira, Renato Tavares ^[1] ; Amaral Luna, Milene Schmidt ^[1] ; de Oliveira, Marcelo Pires ^[2] ; Yamanouye, Norma ^[1] ; Godinho, Rosely Oliveira ^[2] ; Smaili, Soraya Soubhi ^[2] ; Porto, Catarina Segreti ^[2] ; Francis Abdalla, Fernando Mauricio ^[1]

Afiliação do(s) autor(es)

^[1] Inst Butantan, Pharmacol Lab, BR-05503900 Sao Paulo - Brazil

^[2] Univ Fed Sao Paulo, Dept Pharmacol, Escola Paulista Med, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: Life Sciences; v. 86, n. 21-22, p. 832-838, MAY 22 2010.
• Citações Web of Science: 16

Resumo

Aims: The aim of the present study was to investigate the effects of different periods of ovariectomy and 17 beta-estradiol replacement on apoptotic cell death and expression of members of the Bcl-2 family in the rat hippocampus. Main methods: Hippocampi were obtained from rats in proestrus, ovariectomized (15 days, 21 days and 36 days), ovariectomized for 15 days and then treated with 17 beta-estradiol for 7 or 21 days, and rats ovariectomized and immediately treated with 17 beta-estradiol for 21 days. The expression of Bcl-2 and Bax and the number of apoptotic cells were determined. Key findings: Ovariectomy decreased Bcl-2 expression and increased Bax expression and the number of apoptotic cells. Replacement with 17 beta-estradiol (21 days) throughout the post-ovariectomy period reduced the number of apoptotic cells to the control levels, and prevented the effects of ovariectomy on Bax expression, but only partially restored the Bcl-2 expression. After 15 days of ovariectomy. the replacement with 17 beta-estradiol for 21 days, but not for 7 days, restored the Bcl-2 and Bax expression and the percentage of apoptotic cells to the levels found in the proestrus control. Significance: The present results show that a physiological concentration of 17 beta-estradiol may help maintain long-term neuronal viability by regulating the expression of members of the Bcl-2 family. Even after a period of hormonal deprivation, treatment with 17 beta-estradiol is able to restore the expression of Bax and Bcl-2 to control levels, but the duration of the treatment is a key factor to obtain the desired effect. These data provide new understanding into the mechanisms contributing to the neuroprotective action of estrogen. (C) 2010 Elsevier Inc. All rights reserved. (AU)

• Processo FAPESP: 03/10132-0 - Estrógeno e neurotransmissão colinérgica muscarínica: expressão de receptores, sinalização intracelular e suas interações no sistema nervoso central e no trato reprodutor masculino
• Beneficiário: Catarina Segreti Porto
• Modalidade de apoio: Auxílio à Pesquisa - Programa PRONEX - Temático