Background: Ethanol exposure induces apoptotic neurodegeneration in the developing rodent brain during synaptogenesis. This process has been studied as a model for fetal alcohol syndrome. Previously, we have shown that gangliosides and LIGA20 (a semisynthetic derivative of GM1 ganglioside) attenuate ethanol-induced apoptosis in cultured neurons. In the present study, the effects of GM1 and LIGA20 on ethanol-induced apoptotic neurodegeneration were examined using an in vivo neonatal mouse model.
Methods: Seven-day-old C57BL/6By (B6By) mice were pretreated twice with intraperitoneal administration of GM1 (30 mg/kg), LIGA20 (2.5 mg/kg), or saline, followed by subcutaneous injection of either saline or ethanol (2.5 g/kg) twice with a 2 hours interval. Then the brains were: (1) perfusion-fixed 24 hours after the first ethanol injection, and the extent of neurodegeneration was assessed by cupric silver staining of the brain sections, or (2) perfusion-fixed 8 hours after the first ethanol injection, and the sections were immunostained with anti-cleaved (activated) caspase-3 antibody to evaluate caspase-3 activation.
Results: The comparison of cupric silver stained coronal sections indicates that ethanol-induced widespread neurodegeneration in the forebrains of B6By mice was reduced overall by GM1 and LIGA20 pretreatments. The extent of neurodegeneration detected by silver impregnation and activated caspase-3 immunostaining was quantified in the cingulate and retrosplenial cortices, which were the regions most severely affected by ethanol. The results indicate that GM1 and LIGA20 pretreatments induced statistically significant reductions-approximately 50% of the ethanol-treated samples-in silver impregnation and activated caspase-3 immunostaining. No significant differences were observed between saline controls and samples treated with GM1 or LIGA20 alone.
Conclusions: These results indicate that GM1 and LIGA20, which have been shown to be neuroprotective against insults caused by various agents, partially attenuate ethanol-induced apoptotic neurodegeneration in the developing mouse brain.