Specificity of carbohydrate structures of gangliosides in the activity to regenerate the rat axotomized hypoglossal nerve

We previously reported that a ganglioside mixture from bovine brain could p revent neuronal death and promote regeneration in rats with hypoglossal ner ve resection. In the present study, we have compared the neurotrophic effec ts of various glycosphingolipids including lactosylceramide, The findings r evealed that GT1b had the activity of neuronal death prevention equivalent to a ganglioside mixture or autograft, while other glycolipids exhibited ab out 60% activity. However, the capability to promote the regeneration varie d among glycolipids, that is, GT1b (86%), GD1b (55%), GD1a (35%), GQ1b (34% ), GM1 (20%), lactosyl-ceramide (17%) in the number of horseradish peroxida se-positive neurons as an indicator of regeneration. The experiments with o ligosaccharides of GT1b or GD1b and ceramide showed that the carbohydrate m oiety mainly exerts neurotrophic effects. These findings suggested that fin e structures of carbohydrate moiety in gangliosides are critical in the reg enerative activity in this hypoglossal nerve regeneration system.