The concentration of L-Glu remaining was increased during inflammation without cell death. (A) Effects of LPS (1 to 100 ng/mL, 72 h) on the concentration of L-Glu remaining. The L-Glu remaining was significantly increased after incubation with 10 and 100 ng/mL LPS. **P < 0.01 vs. control group (n = 6), Tukey’s test following an ANOVA. (B, C, D) Effects of LPS on LDH leakage and MTT reduction in the astrocyte-microglia-neuron mixed cultures, astrocyte cultures, and microglia cultures. Significant LDH leakage and decreases in MTT reduction were induced by 100 ng/mL LPS but not by LPS concentrations <10 ng/mL in the mixed cultures (B). In the pure astrocyte culture, LPS concentrations <10 ng/mL affected neither LDH leakage nor MTT reduction (C). In the pure microglial culture, significant LDH leakage was induced by 100 ng/mL but not by LPS concentrations <10 ng/mL (D). (E) Time-dependent effects of LPS. The concentration of L-Glu remaining was measured after 6 to 72-h treatments with LPS (10 ng/mL). **P < 0.01 vs. control group (n = 6), paired t-test. (F) The effects of LPS (10 ng/mL, 72 h) on the number of neurons, astrocytes, and microglia. LPS treatment had no effect on the cell numbers (n = 5). (G) Immunostaining of astrocytes, microglia, and neurons in the mixed culture with antibodies against GFAP (red), Iba-1 (blue), and Tuj1 (green) after treatment with 10 ng/mL LPS for 72 h. LPS dramatically changed the shape of the microglia from a ramified shape to an amoeboid shape.