Peroxisome-proliferator activator receptor γ (PPARγ) has an anti-inflammatory role that inhibits the nuclear factor-jB (NF-jB) pathway and regulates the expressions of pro-inflammatory proteins, whereas its role in parasitic meningoencephalitis remains unknown. In this study we investigated the role of PPARγ and related mechanisms in eosinophilic meningoencephalitis caused by the rat lungworm Angiostrongylus cantonensis. We observed increased protein NF-jB expression in mouse brain tissue using GW9662, which is the specific antagonist of PPARγ, in a mouse model of angiostrongyliasis. Then we investigated NF-jB-related downstream proteins, such as COX-2, NOSs, and IL-1b, with Western blot or enzyme-linked immunosorbent assay and found that the protein expression was upregulated. The results of gelatin zymography also showed that the MMP-9 activities were upregulated. Treatment with GW9662 increased the permeability of the blood-brain barrier and the number of eosinophils in cerebrospinal fluid. These results suggested that in angiostrongyliasis, PPARγ may play an anti-inflammation role in many inflammatory mediators, including NOS-related oxidative stress, cytokines, and matrix metalloproteinase cascade by decreasing the NF-jB action.