Figure 4.

MG toxicity in astrocytes and neurons. A, Dose-dependent decrease in astrocytic and neuronal viability following exposure to MG. Cells were treated with MG and cellular viability was assessed 24 h later using the MTT assay. Results are expressed as a percentage of control values and are means ± SEM of at least nine determinations from at least three independent experiments. Data were statistically analyzed with one-way ANOVA followed by Dunnett's test (**p ≤ 0.01 vs controls). B, Pretreatment with the carbonyl scavenger AG protects astrocytes and neurons against MG-induced toxicity as assessed using the MTT assay. Different concentrations of MG were chosen to produce robust toxicity in both cell types (3.5 and 1 mm MG for astrocytes and neurons, respectively). Where indicated, an equimolar amount of AG (3.5 and 1 mm for astrocytes and neurons, respectively) was added 30 min before the addition of MG and maintained throughout the incubation period (24 h). Results are expressed as a percentage of control (CTL) values and are means ± SEM of at least nine determinations from at least three independent experiments. Data were statistically analyzed with ANOVA followed by Bonferroni's test (***p ≤ 0.001 vs controls; ^###p ≤ 0.001 vs MG). C, Astrocytes protect neurons against MG toxicity in astrocyte–neuron cocultures. Primary neurons and cocultures were exposed to the indicated doses of MG, and cellular viability was assessed in the neuronal compartment using the MTT assay. Results are expressed as a percentage of control values and are means ± SEM of at least eight determinations from at least three independent experiments. Data were statistically analyzed with two-way ANOVA followed by Bonferroni's test (***p ≤ 0.001 vs primary neurons).