title: Estradiol treatment decreases cell proliferation in the neurogenic zones of adult female zebrafish (Danio rerio) brain.
abstract: While estrogens are known to play a crucial role in the neurogenesis of the mammalian and avian brain, their role in teleost adult proliferation pattern is not yet fully understood. The present study aimed to determine the estrogen effects in adult brain proliferation zones, using zebrafish, as a model organism. Indeed, teleost fish brain provides a unique adult neurogenesis model, based on its extensive proliferation, contrasting the restricted adult telencephalic neurogenesis observed in birds and mammals. To determine the effect of estrogens, 17-β estradiol was administrated for 7 days in adult female zebrafish, followed by bromodeoxyuridine (BrdU)-immunohistochemistry and double immunofluorescence. Stereological analyses of the BrdU-positive cells within the neurogenic zones, showed region-specific decreases of actively proliferating cells in the estrogen-treated animals, compared to matched controls. Interestingly, the most prominent estradiol effects were found in the number of cycling cells of the ventral nucleus of ventral telencephalic area (Vv) and cerebellar areas. Significant decreases were also determined in the dorso-lateral telencephalic, preoptic and dorsal hypothalamic areas. In contrast, medial dorsal telencephalic, caudal (Hc) and ventral (Hv) hypothalamic areas were unaffected by estrogen treatment. The majority of the BrdU-labeled cells were found to co-express PCNA proliferating marker in Hc, Hv and Vv. Additionally, a population of proliferating cells co-expressed the early neuronal marker TOAD in all areas studied. These results provide significant evidence on the 17-β estradiol impact on adult neurogenesis, down-regulating the fast-cycling and post-mitotic cells within the female zebrafish brain neurogenetic zones.
authors.affiliation: Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, 26500 Rion, Greece.
authors.forename: P
authors.initials: P
authors.lastname: Makantasi
authors.affiliation: Laboratory of Human and Animal Physiology, Department of Biology, University of Patras, 26500 Rion, Greece. Electronic address: dermon@upatras.gr.
authors.forename: C R
authors.initials: CR
authors.lastname: Dermon
mesh_terms: D000818:Animals; D001921:Brain / Q000187:drug effects* / Q000502:physiology; D001973:Bromodeoxyuridine; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects*; D004958:Estradiol / Q000494:pharmacology*; D004967:Estrogens / Q000494:pharmacology*; D005260:Female; D005455:Fluorescent Antibody Technique; D007150:Immunohistochemistry; D010784:Photomicrography; D015027:Zebrafish
chemical_list: D004967:Estrogens; D004958:Estradiol; D001973:Bromodeoxyuridine
keywords: BrdU immunofluorescence; active cell proliferation; estradiol; neurogenesis; stereology; zebrafish