Axogenic response to 17 beta-estradiol in hypothalamic neurons of transgenic XY-Sry male mice

LUCCI, S.; CAMBIASSO, M.J.

Mendoza

Congreso; XXVI Reunion Cientifica Anual Sociedad Biologia de Cuyo; 2008

Sociedad Biologia de Cuyo

Axogenic response to 17-¦Â-oestradiol in hypothalamic neurons of transgenic XY-Sry male mice Lucci MS, Cambiasso MJ Instituto Ferreyra (INIMEC-CONICET) CC389 (5000) C¨®rdoba. E-mail: slucci@immf.uncor.edu Previous work from our laboratory has demonstrated that only neurons from the hypothalamus of male rats (gestational age 16, E16) respond with increased axonal growth to the addition of 17-¦Â-oestradiol (E2) to the culture medium. Transgenic XY-Sry mice are a powerful tool to study the sexual differentiation of the brain. In order to confirm axogenic effect of E2 in this model, hypothalamic neurons from male embryos of E15 and E16 were cultured with (10 and 100 nM E2) or without E2. After 48 h in vitro, neurite outgrowth was quantified by morphometric analysis. Hypothalamic neurons from E15 embryos had less (p<0.001) and shorter (p<0.001) minor processes than neurons from E16, according with age. Significant differences in axonal length were found due to gestational age and hormone treatment, with a significant interaction between the two factors (p<0.001 in all effects). At E16, hypothalamic neurons grown in cultures with 100 nM E2 had longer axons than neurons grown with 10nM E2 or without E2 (p<0.001). Neurons derived from E15 embryos showed no significant effects of E2. These preliminary data show that neuronal cultures of XY-Sry mouse embryos are a good model to study the effect of gonadal hormones and Sry gene on E2-induced axogenesis in the developing hypothalamus at E16.