Potential therapeutic effects of curcumin, with or without L-DOPA, on motor and cognitive functions and hippocampal changes in rotenone-treated rats

The neurodegenerative condition known as Parkinson’s disease (PD) is a long-term condition that causes both motor and non-motor symptoms. It is known that curcumin has a strong neuroprotective potential. This experimental study was designed to examine the anti-inflammatory, anti-apoptotic and neuroprotective effects of curcumin administered alone and in combination with L-DOPA in the hippocampus as well as behavioral symptoms in rotenone-induced PD model. Forty-two 4-month-old adult male Wistar rats were randomly divided into six groups as follows: Control, Curcumin, Rotenone, Rotenone plus curcumin, Rotenone plus L-DOPA and Rotenone plus curcumin plus L-DOPA. Control group received vehicles, curcumin group received curcumin (200 mg kg−1, daily for 35 days), rotenone group received rotenone (2 mg kg−1, daily for 35 days), and test groups received curcumin or L-DOPA (10 mg kg−1, daily for the last 15 days) or their combination in addition the rotenone. Pole, sucrose preference, open field, elevated plus maze, and Morris water maze tests were performed after treatment. Molecular and biochemical analyses were performed in the hippocampus tissue and serum samples. Rotenone injection caused impairments in motor activity, depressive-like behavior, and learning and memory functions. Rotenone also increased the expressions of α-synuclein, caspase 3, NF-κB, and decreased the expressions of parkin and BDNF in the hippocampus. However, especially curcumin and L-DOPA combined treatment normalized all these impaired molecular and behavioral variables. In conclusion, curcumin may exert beneficial effects in treatment strategies for PD-related hippocampal effects, especially when added to L-DOPA therapy.