Irisin protects the substantia nigra dopaminergic neurons in the rat model of Parkinson’s disease

OBJECTIVE(S): Exercise ameliorates the quality of life and reduces the risk of neurological derangements such as Alzheimer’s (AD) and Parkinson’s disease (PD). Irisin is a product of the physical activity and is a circulating hormone that regulates the energy metabolism in the body. In the nervous system, Irisin influences neurogenesis and neural differentiation in mice. We previously demonstrated that co-treatment of bone marrow stem cells (BMSCs) with a neurotrophic factor reduce Parkinson’s symptoms. Our goal in this project was to evaluate whether Irisin with BMSCs can protect the dopaminergic (DA) neurons in PD. MATERIALS AND METHODS: 35 adult male Wistar rat weighing (200-250 g) were chosen. They were separated into five experimental groups (n=7). To create a Parkinson’s model, intranasal (IN) administration of the MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) was used. The BMSCs (2×106) and Irisin (50 nm/ml) was used for 7 days for treatment after creation of the PD model. After completion of the tests (4 weeks), their brains were used for the TUNEL and immunohistochemical (IHC) assays. RESULTS: One of the important results of this study was that the Irisin induce BMSCs transport into the injured area of the brain. Co-treatment of the Irisin with BMSCs increased tyrosine hydroxylase-positive neurons (TH+) in substantia nigra (SN) and striatum of the PD mice brain. In this group, the number of TUNEL-positive cells significantly decreased. Behavioral symptoms were better in the combination group and Irisin simultaneously. CONCLUSION: Co- treatment of Irisin with BMSCs protects the DA neurons from degeneration and apoptotic process after MPTP injection.