Traumatic injury of spinal cord cells in vitro reduced by GM1 ganglioside

Abstract

GM1 ganglioside (monosialoganglioside) is a significant endogenous component of central nervous system (CNS) cellular membranes, thereby contributing to the membranes' integrity and function. Exogenous gangliosides have been shown to be incorporated into plasma membranes and can exert neuroprotective effects on damaged neuronal tissue(s). An in vitro method of physical injury (trauma) previously described which used cultures derived from fetal mouse spinal cord [38] was adapted for these studies in order for us to assess GMl's neuroprotective efficacy. Injury 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 μM) was assessed after 48 h by measuring lactate dehydrogenase (LDH) released and by observing changes in the plasma membrane surface distribution of endogenous GM1 using cholera toxin/antitoxin/fluorescent antibody immunohistochemistry. A gradient of injury, from the zone of maximum injury to partially traumatized or non-injured areas, was seen using immunohistochemistry. The primary injury zone in this gradient was characterized by areas of swollen or dead cells and abnormal or degenerating cell processes. At further distances, cells were observed to be nearly normal, with intact fibers. This gradient of injury may reflect proximate (at the locus of trauma) and distant effects of the release of neurotoxic levels of endogenous glutamate (Glu) and other excitatory amino acids. Ganglioside GM1 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 GMl's previously documented neuroprotective effects using neuronal culture systems can be generalized to injured spinal cells in vitro wherein there is evidence 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.