Quercetin and Sesamin Protect Dopaminergic Cells from MPP⁺-Induced Neuroinflammation in a Microglial (N9)-Neuronal (PC12) Coculture System

Figure 5

Neuronal PC12 cells were cocultured with MPP⁺-activated N9 microglial cells pretreated or not with quercetin or sesamin for 24 h. Then, neuronal PC12 cell supernatants were collected for cell death measurement by the LDH cytotoxicity test. Ctrl: nonactivated microglial cells were placed on neuronal PC12 cells; no neuronal death was detected. MPP⁺: MPP⁺-activated microglial cells were placed on neuronal PC12 cells; a significant increase of neuronal cell death was apparent, indicating that cytokines produced by microglial cells induce neuronal death. Ctrl MPP⁺: MPP⁺ was added to the medium of the insert without microglial cells. Pretreatment of N9 cells with quercetin or sesamin prior to MPP⁺ clearly reduced neuronal PC12 cell death. Pretreatment of non-MPP⁺-activated N9 cells with quercetin or sesamin did not produce cellular death (quercetin, sesamin) 𝑛=3. **𝑃<0.01 compared to the control (Ctrl), °𝑃<0.05 compared to their respective controls (quercetin, sesamin, or Ctrl), as determined by 1-way ANOVA, followed by Tukey’s multiple comparison test.