A RAT MODEL OF PARKINSONS-DISEASE INDUCED BY JAPANESE ENCEPHALITIS-VIRUS

In Fischer rats infected with Japanese encephalitis virus (TEV) at 13 days after birth and sacrificed 12 weeks later, the major pathological changes resembled those found in Parkinson's disease. Specifically th ere was neuronal loss with gliosis which was confined mainly to the zo na compacta of the substantia nigra, with a notable absence of lesions in the cerebral cortex and cerebellum. Changes were bilateral being m ost severe in the central part of the zona compacta. Immunohistochemic al studies with anti-tyrosine hydroxylase (Ttl) demonstrated that the number of TH-positive neurons was significantly decreased in the subst antia nigra compared to controls, while comparable numbers of Ttl-posi tive neurons were found in the basal ganglia in both JEV-treated rats and age-matched controls. JEV-infected rats showed marked bradykinesia , with significant behavioral improvement being observed following adm inistration of L-DOPA. Immunohistochemical studies failed to detect JE V antigens in any region of the rat brain and the JEV genome was undet ectable in the substantia nigra and the cerebral cortex using the reve rse transcription-polymerase chain reaction (RT - PCR). The findings s uggest that TEV infection of rats under the conditions described may s erve as a model of virus induced Parkinson's Disease.