Administration of exogenous gangliosides has been reported to accelerate neurite outgrowth in vitro, and to enhance peripheral nerve regeneration and central nervous system recovery subsequent to damage. After injury, facilitation of CNS recovery with GMl ganglioside treatment has been postulated to be due to enhanced neuronal regeneration. Since maximal recovery is achieved when experimental animals are treated before injury with GMl ganglioside, an alternative or parallel mechanism is that gangliosides are "protecting" the CNS by limiting the extent of damage (ie, cell loss, process degeneration, membrane disruption). This may be due to a reduction in the edema subsequent to injury.
In this study, rats were treated for 2 days with 20 mg/kg/day of GMl ganglioside. On the third day they were subjected to a unilateral lesion (mechanical) of one cerebral hemisphere and given another 20 mg/kg of GMl . On the fourth day brains were removed for analysis of edema resulting from the injury. In treated animals there was a significant reduction in edema as measured either in the entire injured hemisphere (23%) or in the area of injury (33%). No effect was seen outside the damaged area. Since exogenous gangliosides can spontaneously "insert'' into membranes, it is postulated that the effect of the GM1 may be due to alterations of membrane processes (eg , lipid hydrolysis, phospholipase activation, levels and membrane action o f arachidonic acid, ionic permeation) that are characteristic of edema.