TRAUMATIC INJURY OF SPINAL-CORD CELLS IN-VITRO REDUCED BY GM1 GANGLIOSIDE

GM1 ganglioside (monosialoganglioside) is a significant endogenous com ponent of central nervous system (CNS) cellular membranes, thereby con tributing to the membranes' integrity and function. Exogenous ganglios ides have been shown to be incorporated into plasma membranes and can exert neuroprotective effects on damaged neuronal tissue(s). An in vit ro method of physical injury (trauma) previously described which used cultures derived from fetal mouse spinal cord [38] was adapted for the se studies in order for us to assess GM1's neuroprotective efficacy. I njury was induced by uniformly crosshatching the spinal cell cultures with a 1 mm plastic pipette tip. The extent of injury and the effects of GM1 ganglioside posttreatment (80 mu M) was assessed after 48 h by measuring lactate dehydrogenase (LDH) released and by observing change s in the plasma membrane surface distribution of endogenous GM1 using cholera toxin/antitoxin/fluorescent antibody immunohistochemistry. A g radient of injury, from the zone of maximum injury to partially trauma tized or non-injured areas, was seen using immunohistochemistry. The p rimary injury zone in this gradient was characterized by areas of swol len or dead cells and abnormal or degenerating cell processes. At furt her distances, cells were observed to be nearly normal, with intact fi bers. This gradient of injury may reflect proximate (at the locus of t rauma) and distant effects of the release of neurotoxic levels of endo genous glutamate (Glu) and other excitatory amino acids. Ganglioside G M1 treatment resulted in a significantly reduced (>75%) release of LDH as well as enhanced cell and process integrity indicative of reduced tissue injury. These initial results indicate that GM1's previously do cumented neuroprotective effects using neuronal culture systems can be generalized to injured spinal cells in vitro wherein there is evidenc e for preservation (rescue) of cellular plasma membranes after injury as reflected by reduced cell loss, swelling, and process degeneration, as well as decreased LDH release.