Gangliosides stimulate protein synthesis, growth, and axon number of regenerating limb buds

When a newt limb is amputated and begins to regrow, regenerating axons exert a neurotrophic influence on the limb regeneration process. Previous studies have shown that direct manipulation of limb nerves, by electrical stimulation or a conditioning lesion, elevates protein synthesis, increases neurotization and accelerates growth of the limb bud. Since exogenously supplied gangliosides accelerate axonal sprouting in regenerating nerves, we wanted to know whether gangliosides would similarly affect limb regeneration. To test this, regrowing limb buds were either infused with or immersed into gangliosides, or animals were injected intraperitoneally with gangliosides. Infused gangliosides elevated protein synthesis in limb buds 15% and increased the number of axons in limb buds 45% by 6 hours after infusion. Regenerating limb bud morphogenesis was initiated 3-4 days earlier in animals receiving i.p. injections of gangliosides every 12 hours. Similarly, limbs immersed daily in gangliosides began regrowth sooner than contralateral controls and this advantage was maintained throughout the period of observation. These findings indicate that treatment with gangliosides has a salutary effect on limb regeneration.