Inflammatory reaction following 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine intoxication in mouse

In degenerative disorders of the CNS an immune system involvement in the pa thological process is postulated. The MPTP model of Parkinson's disease see m to be a good model for studying an inflammation following toxic neurodege neration. In this model, microglial and astroglial reactions were previousl y found around impaired neurons. In the present work we showed an immune re action, including lymphocytic infiltration of CD4+ and CD8+ T cells in the substantia nigra and striatum and elevated MHC class I and II antigens expr ession on microglia. Many activated lymphocytes were present, showing incre ased LFA-1 and CD44 antigen expression. We found also that ICAM-1 expressio n increased on the endothelium and appeared on microglia in the injured reg ions. Treatment with dexamethasone inhibited T-cell infiltration and MHC cl ass II expression, lessened the glial reaction, and also diminished neurona l impairment. These findings suggest that an immune mechanism may contribut e to the neuronal damage following MPTP administration. (C) 1999 Academic P ress.