Figure 8.

The neurotoxicity of MPP⁺ to N2A cells was enhanced by microglia activated with PM₁₀-conditioned medium. (A) Cell viability was analyzed using an MTT assay to investigate the dose-dependent toxicity of MPP⁺ on N2A cells cultured alone. (B) Experimental schematic describing the coculture system of neuronal N2A cells and BV2 microglia activated by PM₁₀-conditioned medium using Transwell chambers (pore size 0.4 μm). The medium was first collected from cocultured of LA-4/RAW264.7 cells following 24 h of PM₁₀ exposure. The PM₁₀-conditioned medium was then applied to BV2 cells for 24 h to activate microglia. N2A cells were plated on the bottom, and then activated BV2 cells were plated on the top of the Transwell inserts. These N2A and BV2 cells were cultured in DMEM (without any PM₁₀ stimulus) with Neurotoxin MPP⁺ for 24 h. (C) N2A cells cocultured with microglia activated by PM₁₀-conditioned medium were treated with MPP⁺ (200 μM) for 24 h. N2A cell survival was determined by MTT analysis. The value was normalized to each non-MPP⁺ treated group. The data are expressed as the mean ± SEM (n = 4–5 per group). * p < 0.05; ** p < 0.01; **** p < 0.0001.