Figure 1.

Schematic representations of systemic LPS administration regimens. For the single LPS (sLPS) treatment (a), mice were injected intraperitoneally once with 5 mg/kg. After three months, they were challenged with MPTP (30 mg/kg for five consecutive days) and were then analyzed. For the repeated LPS (mLPS) treatment (b), mice were injected intraperitoneally 100 μg/kg twice a week for three months. They were then challenged with MPTP (30 mg/kg for five consecutive days) and analyzed. Control groups (saline, sLPS, and mLPS) were euthanized after three months of the challenges. MPTP groups were euthanized either three days after MPTP exposure for damage markers (MTT assay, cleaved caspase-3, and TBARS) and cytokine levels or seven days after MPTP challenge for behavioral tests, neurotransmitter levels, and Iba1 staining.