Inosine and guanosine preserve neuronal and glial cell viability in mouse spinal cord cultures during chemical hypoxia.

Murine spinal cord primary mixed cultures were treated with the respiratory inhibitor, rotenone, to mimic hypoxic conditions. Under these conditions neurons rapidly underwent oncosis (necrosis) with a complete loss in viability occurring within 260 min; however, astrocytes, which accounted for most of the cell population, died more slowly with 50% viability occurring at 565 min. Inosine preserved both total cell and neuronal viability in a concentration-dependent manner. The time of inosine addition relative to hypoxic insult was critical with the most effective protection occurring when inosine was added just prior to or within 5 min after insult. Inosine was ineffective when added 30 min after hypoxic insult. The effect of guanosine was similar to that of inosine. Treatment of cultures with BCX-34, a purine nucleoside phosphorylase inhibitor, prevented protection by inosine or guanosine, suggesting involvement of a purine nucleoside phosphorylase in the nucleoside protective effect.