Figure 4.

In vitro chronic, 10-day, hCG exposure to immature cortical and hippocampal neurons is not toxic and protects them from NMDA-dependent excitotoxic injury. (A,B) MAP2 fluorescence following immunocytochemical staining of dissociated cortical and hippocampal neurons exposed to control vs. 2 IU/mL of hCG for 9 days prior and 24 h following IBO (50 µM; IBO) exposure. Prolonged hCG did not appear to affect neuronal survival. Note also the relative preservation of neurites in hCG-exposed neurons after IBO exposure (most noticeable in cortical neurons) compared with control (CSS; controlled salt solution). (C) Quantitative bar graph analysis of the effects of hCG on neuronal survival as a measure of LDH activity in the neuronal media or MAP2 IR in control and hCG-treated neuronal cultures 24 h after injury with IBO. Cortical and hippocampal neurons exposed to hCG demonstrated a reduction in IBO-mediated increases in LDH activity and a relative preservation of neurite staining compared with non-hCG-treated cells. Scale bars = 165 µm. Error bars show SE; *p < 0.05 and **p < 0.01. hCG, human chorionic gonadotropin; IBO, ibotenic acid; IR, immunoreactivity; LDH, lactase dehydrogenase.