Striatal vs. Nigral 6-OHDA lesion models: a closer look at Parkinson's disease pathology

Although the 6-OHDA lesion of the substantia nigra has been frequently used as an experimental model of Parkinson's disease (PD), striatal lesions have become a model of interest due to retrograde (striato-nigral) neuronal degeneration. Our objective was to evaluate the degeneration produced by striatal injury versus nigral injury to establish which experimental model shows greater homology with PD. Dopaminergic degeneration was induced through the injection of 6-OHDA into male Wistar rats, with one or two lesion sites in the striatum, or by targeting the substantia nigra. To determine the degree of dopaminergic neuronal death, Nissl staining, tyrosine hydroxylase (TH), and glial fibrillary acidic protein (GFAP) immunohistochemistry were performed. This evaluation was conducted at 15 days, 1 month, and 6 months post-lesion. Our results indicated that the striatal models exhibit higher homology with PD compared to the nigral model, according to histological findings. The most significant evidence was the partially intact preservation of the ventral tegmental area.