The role of the liver--brain axis in a rotenone-induced rat model of Parkinson's disease

Introduction: Recent studies investigate potential axes between the brain and peripheral organs that could be related to neurodegeneration. Emerging evidence showing the importance of the liver--brain axis in the development and prognosis of neurodegenerative diseases points to the liver as a possible critical organ in the neurodegeneration process. The present study on gene expression in the brain and liver aims to unveil molecular pathways involved in Parkinson’s disease (PD). Method: Basic levels of the cerebral and hepatic expression of genes related to α-synuclein production and transport, oxidative stress, and inflammation were assessed to reveal potential targets involved in the communication of both organs in rotenone-treated rats via a rodent model of PD as compared to control rats. Total RNA was extracted from brain and liver tissue, and the gene expression of SNCA, Nrf2, NF-κB, DJ-1, Atp13a2, LRRK2, PARK2, LRP-1 PINK1, IFN-γ, and TNF-α was determined by qPCR. Expression levels were normalized to the housekeeping gene, and the relative expression levels of their mRNAs were determined using the (2^–ΔΔct) method. Result: Several genes affected in the liver of the rotenone treatment group, as compared to the control group, also demonstrated altered brain expression. Conclusion: The study suggests that changes in the liver may be involved in pathological conditions linked to PD and supports research on peripheral markers related to the liver--brain axis in this disease.