Abstract

Chronic opioid abuse can impair the hippocampal region of the brain. This study evaluates the neuroprotective effect of Achillea millefolium (Ach) on chronic morphine-induced learning and memory impairment, oxidative stress, and neuronal apoptosis in the CA1 region of the rat hippocampus. Thirty-two male Wistar rat rats were classified into four treatment groups (n=8). Morphine sulfate was administered chronically. The treatment groups were given Ach aqueous extract (100, 250, and 500 mg/kg), orally, each day. After 28 days, the Morris water maze test was performed on all subjects. Caspase-3, Bax, and Bcl-2 proteins expression in the CA1 region of hippocampal tissue was analyzed using the western blot method. Also, malondialdehyde concentration, glutathione peroxidase activity, and superoxide dismutase activity were evaluated. The results indicated that Ach extract can improve spatial learning and memory defects in morphine-treated rats. Ach administration also ameliorated apoptosis and oxidative stress indicator levels in hippocampal CA1 of morphine-treated animals. Based on the present study, Ach improved spatial learning and memory defects, and reduced oxidative stress and apoptosis in the hippocampus CA1 region, in chronic morphine-treated animals.