Early Changes in the Striatum in a Rat Model of Parkinson's Disease

Abstract

Parkinson's Disease (PD) is a neurodegenerative disorder marked by a decrease in dopamine (DA) levels within the cell bodies in the substantia nigra pars compacta and at terminations in the striatum. It has been observed that in patients with PD, the introduction or increase in stress levels corresponds with an increased rate of DA loss. With the identification of neurochemical changes in PD, scientists are now able to create an animal model of the disease. A lesion can be created by the application of 6- hydroxydopamine (6-0HDA) to the striatal tissue. Trimethylthiazoline (TMT), a predator odor in fox urine, can then be used as a secondary stressor event on the animals in order to study the effects of environmental stress on PD. In this study, western blot analysis was conducted in order to examine changes in the levels of caspase-3, fractin, tyrosine hydroxylase (TH) and Neuronal Nuclei (NeuN). It was found that in the PD animals treated with TMT, there was an increase in levels of caspase-3 in comparison to those not exposed to TMT and animals in which the lesion did not take. Fractin and TH levels decreased and there was little change in NeuN levels. The results indicate that with an increase in stress, there is an increase in caspase-3 (an apoptotic factor), a corresponding decrease in DA levels. However, little cell death was observed. Future research into this area may attempt to explain why there is DA loss without presence of cell death.