Toxin-Based Rodent Models of Parkinson’s Disease

A major pathological hallmark of Parkinson’s disease (PD) is a severe degeneration of dopamine (DA)-producing neurons in the substantia nigra pars compacta (SNc) projecting to the motor part of the striatum. Therefore, there is a long-standing interest in using animal models with severe nigrostriatal degeneration for experimental research. Pathophysiological and behavioral features of PD are best studied in mammalian species endowed with well-developed corticobasal ganglia thalamocortical loops, such as rodents. Different toxins can be used to generate nigrostriatal damage, including 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), paraquat, and rotenone. Models based on 6-OHDA lesions provide the main advantage of a severe and reproducible DA lesions. Models based on MPTP provide easy and versatile tools to rapidly evaluate potential neuroprotective treatments. Models based on paraquat and rotenone are appealing for their relevance to some well-known environmental risk factors of the human PD, although they yield only partial dopaminergic degeneration and entail a considerable risk of nonspecific toxicity. The main general limitation of neurotoxin-based models is that they do not replicate some characterizing features of PD pathology, such as the formation of Lewy body–like proteinaceous aggregates or the anatomical pattern of neurodegeneration, which also affects nondopaminergic brain regions