Figure 11

PQ (10 mg/kg b.w.) treatment increases TNF-α immunoreactivity in brain. TNF-α immunolocalization was assessed in SN, FC and hippocampus (A, B and C respectively). Densitometric analyses of western blots for TNF-α (D) were performed to assess expression levels of TNF-α in SN, FC and hippocampus. (A): TNF-α immunoreactivity was more intense in SN of PQ-treated animals (b) compared to controls (a). TNF-α immunopositivity was found in both neuritic areas and in large, oval-shaped cells (putative microglia-macrophages, black arrows) in SN of PQ-treated animals (b). (B): The FC of PQ-treated animals (b) showed more intense TNF-α immunoreactivity compared to controls (a). Immunoreaction appeared in neurites and in small round cells (putative microglia, black arrows) in FC of PQ-treated animals (b). (C): TNF-α immunoreactivity was found in both nucleated and non-nucleated areas of hippocampus, with more intense immunoreaction in hippocampal regions of PQ-treated animals (dentate gyrus, CA3 and CA1; b, d and f respectively). TNF-α immunopositive small round cells (putative microglia, black arrows) appeared in both nucleated and non-nucleated areas of hippocampus of PQ-treated animals (b, d and f). (D): Densitometric analyses of western blots indicate that TNF-α expression levels increased significantly in all three regions (SN, FC and hippocampus) of PQ-treated animals compared to controls. β-Actin was used as a reference control in western blots. Data are presented as mean ± SEM (n = 3). Asterisks (*) represent significant differences at a level of p < 0.05 (Student's t-test) for densitometric analyses. Magnification of IHC images is 40× and the scale bars = 40µm.