The effects of deep brain stimulation of the substantia nigra pars reticulata in 6-OHDA parkinsonism model in rats

Deep brain stimulation is a method of treatment for Parkinson's disease (PD). This study was planned to investigate the effects of electrodes on gait disturbances which were placed in the pars reticulata (SNr) region of the substantia nigra (SN) and the mechanism involved in this effect in the experimental rat models of PD. In our study, 280-300 g male Wistar rats were used. The animals were randomly divided into 4 groups. 1-Healthy group of animals (Control), 2- Bilateral striatal 6-OHDA lesion group (Parkinson group), 3-Group with bilateral striatal 6-OHDA and SNr electrode placed (Parkinson + Sham stimulation), 4-Group with bilateral striatal 6-OHDA and SNr stimulation (Parkinson + SNr Stimulation). The electrical stimulation was applied for 3 hours daily for 14 days. After the behavior tests were done, the experiment was terminated. Brains of animals were taken and used for immunohistochemical studies of the SN, cerebellum, frontal cortex and thalamus regions. Vertical, horizontal, mean distances and total LMA values recorded in locomotor activity were found to decrease in PD groups and increase with electrical stimulation. In walking analysis, it was determined that front and rear foot step lengths were decreased and electrical stimulus improved the values in the Parkinson group. Cerebellum and frontal lobe brain-derived neural factor (BDNF) and c-fos containing cells were counted. It was found that the numbers were decreased in the cerebellum, frontal lobe and thalamus regions of Parkinson group and increased after electrical stimulation. The results of our study indicate that stimulation of the SNr region improves gait disturbances in the experimental Parkinsonian model of rats and that BDNF is involved in this mechanism.