Mouse model of Parkinsonism: a comparison between subacute MPTP and chronic MPTP/probenecid treatment.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) is widely used to induce an animal model of Parkinsonism. The conventional mouse model, which usually involves acute or subacute injections of MPTP, results in a significant but reversible loss of dopaminergic functions. We have developed an alternative mouse model, in which co-administration of MPTP with probenecid results in the chronic loss of striatal dopamine for at least 6 months after cessation of treatment. In the present study, we compare the neurochemical, morphological and behavioral changes that occur in this alternative, chronic model with those in the conventional, subacute model. In the chronic model, we demonstrate an almost 80% loss of striatal dopamine and dopamine uptake 6 months after withdrawal from treatment. The neurochemical signs match unbiased stereological measures that demonstrate gradual loss of substantia nigra neurons. Rotarod performance further substantiates these findings by showing a progressive decline in motor performance. Based on the comparisons made in this study in mice, the chronic MPTP/probenecid model shows considerable improvements over the conventional, subacute MPTP model. The sustained alterations in the nigrostriatal pathway resemble the cardinal signs of human Parkinson's disease and suggest that this chronic mouse model is potentially useful to study the pathophysiology and mechanisms of Parkinsonism. It should also prove useful for the development of neuroprotection strategies.