17β Estradiol Protection Against Medium-Change Neurotoxicity in Organotypic Hippocampal Slice Cultures

Medium change neurotoxicity can disrupt glutamate homeostasis and promote excitotoxic neuronal injury through excessive NMDA receptor activation. 17β estradiol (E2) has demonstrated neuroprotective effects in models of neuronal injury and may regulate glutamatergic signaling through metabotropic glutamate receptors (mGluR2/3). This study investigated whether E2 protects against medium change associated neurotoxicity in organotypic hippocampal slice cultures whether responses differed by sex or hippocampal region. Hippocampal slices from postnatal day 8 male and female Sprague Dawley rats were maintained in culture and exposed to 1, 10, or 100 nM E2 for 24 hours following a five day recovery period. Propidium iodide (PI) was measured in the CA1, CA3, and dentate gyrus (DG) regions as an indicator of cellular membrane damage. Fluorescence intensity was quantified using microscopy and ImageJ, and percent control PI uptake was analyzed using analysis of variance to assess the effects of treatment, sex, and hippocampal region. No significant effect of E2 treatment or hippocampal region was observed, and no significant interactions were detected. However, a significant effect of sex was found, with male slices exhibiting greater PI uptake than female slices across experimental conditions. These findings indicate that E2 did not provide detectable neuroprotection at the concentrations tested, while biological sex may influence susceptibility to cellular membrane damage. Further research is needed to investigate sex specific mechanisms of neuronal vulnerability and the conditions under which E2 may exert neuroprotective effects.