author(s)
Khaksar Zabihollah, Farzam Mohammad

abstract
Parkinson’s disease is a progressive degenerative neurological disorder and is associated with reduction of dopamine-secreting neurons and maybe GABA neurons in substantia nigra and basal ganglia pathways. At present, there are various methods of treatment for these patients that the most important one is treatment methods with chemical medicines; however these drugs have many side effects. Thus, researchers turn toward using of medicinal plants such as lycopene which is an antioxidant and neuroprotective reagent to minimize the side effects of these medicines. The main objective of this study is investigation of lycopene effects on density of dopaminergic receptors and GABA neurons in hippocampus and substantianigra areas of Parkinson’s disease modelrats.
Methods: In this study, a number of 65 adult male rats were randomly divided into five groups including control group (without getting any material), lycopene control group (0.5 ml/kg lycopene via gavage), patient group (unilateral injection (6-hydroxy dopaminergic to substantia nigra area by Hamilton needle)), sham group (induction of Parkinson’s disease + 0.02% of ascorbic acid by unilateral injection into substantianigra area), and treated group with lycopene (induction of Parkinson’s disease + 0.5 ml/kg lycopene); and 15, 30 and 60 days were considered for treatment periods. Then the rats were euthanized in every single day and their brains removed for further process and density of D1, D2, and GABA receptors were investigated by hematoxylin and eosin (H&E) staining and optical microscopy.
Results: The number of D1, D2, and GABA receptors in sham and patient groups in 15, 30 and 60 days of treatment period had a significant reduction in hippocampus and substantianigra areas compared to control and lycopene groups. Also, a significant increase in hippocampus and substantia nigra areas in various days of treatment was observed in the experimental group treated with lycopene compared to patient group. The receptors density in various days of treatment in hippocampus area of the patient group was more than substantia nigra area.
Conclusion: according to the above, Parkinson’s disease reduces the density of D1, D2, and GABA receptors in hippocampus and substantianigra areas and lycopene extract causes reduction of side effects and somewhat improvement of Parkinson’s disease, due to its neuroprotective and antioxidant properties. The obtained results can be somewhat generalized to human.