The Potential Effect of Caffeine and Nicotine Co-administration against Aluminum-induced Alzheimer's disease in Rats

Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized clinically by cognitive decline and memory loss. Caffeine and nicotine are the most commonly co-used psycho stimulants. Caffeine is one of the major contributors to the dietary antioxidants which prevent oxidative damage and may reduce the risk of chronic neurodegenerative diseases. Nicotine has the ability to decrease level of reactive oxygen species (ROS) in the hippocampus and suggested to attenuate the impairment of memory associated with AD. The study aimed to evaluate the influence of caffeine and nicotine co-administration against aluminium-induced neurotoxicity that mimics AD in rats. Five groups of rats were used and received daily for five weeks: Saline for control, aluminium chloride (AlCl3) (70 mg/kg, IP) for AD mimic group, while treated groups received together with AlCl3, either Caffeine (5mg/kg, IP), Nicotine (1 mg/kg, SC) or their combination. Three behavioral experiments were performed: Forced Swimming Test (FST), Morris Water Maze (MWM) task and Conditioned-Avoidance and Learning (CAL) test. Histo pathological changes in the brain and biochemical changes in Acetyl cholinesterase (AchE) as well as oxidative parameters; malon dialdehyde (MDA), superoxide dismutase (SOD), total anti oxidane capacity (TAC) were also evaluated for all groups. Results of the behavioral tests showed that caffeine and nicotine co-administration had more pronounced protecting effect from learning and memory impairment induced by AlCl3 than each one alone. Caffeine and nicotine co-administration also prevent neuronal degeneration in the hippocampus and the eosinophilic plagues in the striatum induced by AlCl3 while nicotine alone still showed mild gliosis in striatum. The marked protection of caffeine and nicotine co-administration confirmed also by the significant increase in TAC and SOD and decrease in MDA and AchE in brain tissue. In conclusion, co-administration of caffeine and nicotine can reduce the risk of neuronal degeneration in the hippocampus and attenuate the impairment of learning and memory associated with AD.