Effect of Thymoquinone against Aluminum Chloride-Induced Alzheimer-Like Model in Rats: A Neurophysiological and Behavioral Study

Abstract Background: Alzheimer Disease (AD) is a progressive neurodegenerative disorder characterized by oxidative stress, neuro-inflammation and synaptic dysfunction, which caused in part by abnormal aggregation of senile plaques and neu-rofibrillary tangles outside and inside the cerebral neurons, respectively. Thymoquinone (TQ) is the major bioactive ingredient of the volatile oil of Nigella sativa seed and it possess anti-inflammatory and antioxidant effects in some neuronal diseases. Aim of Study: To evaluate the neuroprotective potential of TQ on the oxidative stress status of the brain in aluminum chloride (AlCl3)-induced AD in rats. Material and Methods: Thirty adult male Sprague Dawley albino rats were used in this study. They were randomly divided into 3 groups. Group 1 (control group). Group 2 (AD group): Supplemented orally with AlCl3 (17mg/kg/day) for 4 weeks. Group 3 (TQ/AD group) supplemented concomitantly with oral TQ (10mg/kg/day) and AlCl3 (17mg/kg/day) for 4 weeks. At the end of the experiment, spatial working memory was assessed using the Y-maze spontaneous alternation test. Then, serum levels of Malondialdehyde (MDA) and Glutath-ione Peroxidase Enzyme (GPX) were assessed. Then, the rats were sacrificed and the brain tissue homogenate content of tau protein, AR and acetyle choline were determined. Results: In AD group, spatial working memory was im-paired as indicated by a significant decline of Spontaneous Alteration Performance (SAP%) at Y-maze behavior test. Also, AR, tau protein, acetyle choline in brain and serum MDA were significantly increased with a significant decrease of serum GPX. Co-administration of TQ with AlCl3 in TQ/AD group, significantly decreased AR, tau protein, acetyle choline in brain and serum MDA and increased (SAP%) and serum GPX. Conclusion: TQ could mitigate the neurodegenerative markers and oxidative stress indices encountered in AD, presumably via its antioxidant and anti-inflammatory effects.
This may implement TQ as an adjuvant alternative medical strategy in ameliorating this devastating disease