GFAP and Parkinson disease: More importantly, compared with the MPTP group, Iba-1+ microglia and GFAP+ astrocytes were activated more significantly in the striatum of the TMAO + MPTP group (Figure 4A–D), indicating that TMAO significantly aggravated the neuroinflammation mediated by the microglia and astrocytes in the striatum of the PD mice.