Selective estrogen receptor modulators decrease reactive astrogliosis in the injured brain: Effects of aging and prolonged depletion of ovarian hormones

George Barreto, María Santos-Galindo, Yolanda Diz-Chaves, Olga Pernía, Paloma Carrero, Iñigo Azcoitia, Luis M. Garcia-Segura

Research output: Contribution to journalArticlepeer-review

Abstract

After brain injury, astrocytes acquire a reactive phenotype characterized by a series of morphological and molecular modifications, including the expression of the cytoskeletal protein vimentin. Previous studies have shown that estradiol down-regulates reactive astrogliosis. In this study we assessed whether raloxifene and tamoxifen, two selective estrogen receptor modulators, have effects similar to estradiol in astrocytes. We also assessed whether aging and the timing of estrogenic therapy after ovariectomy influence the action of the estrogenic compounds. Four groups of animals were studied: 1) young rats, ovariectomized at 2 months of age; 2) middle-aged rats, ovariectomized at 8 months of age; 3) aged rats, ovariectomized at 18 months of age; and 4) aged rats, ovariectomized at 2 months and sham operated at 18 months of age. Fifteen days after ovariectomy or sham surgery, animals received a stab wound brain injury and the treatment with the estrogenic compounds. The number of vimentin-immunoreactive astrocytes after injury was significantly higher in the hippocampus of aged rats after a long-term ovariectomy compared with aged animals after a short-term ovariectomy and middle-aged rats. In addition, reactive astrocytes were more numerous in the two groups of aged animals than in young animals. Despite these differences, the estrogenic compounds reduced reactive astrogliosis in all animal groups. These findings indicate that estradiol, raloxifene, and tamoxifen are potential candidates for the control of astrogliosis in young and older individuals and after a prolonged depletion of ovarian hormones.

Original languageEnglish
Pages (from-to)5010-5015
Number of pages6
JournalEndocrinology
Volume150
Issue number11
DOIs
Publication statusPublished - Nov 2009
Externally publishedYes

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