ABSTRACT
Aluminium (Al) is ubiquitous in the environment. As a consequence, food is the primary source for Aluminium intake under physiological conditions (Yokel et al, 2001). Aluminium overload increases oxidative stress in the hippocampus, diencephalon, cerebellum and brainstem in neonatal rats. Lesions in the brain of Alzheimer's disease (AD) patients are typically associated with attacks by free radicals (Yuan et al, 2012). The ability of antioxidant to combat effects of aluminium is well established. Considering this, Theobroma cacao, a known antioxidant was investigated in aluminium induced neurotoxicity in experimental animal. Accordingly, this study was designed to investigate the possible therapeutic effects of Theobroma cacao (CO) on aluminium-induced neurotoxicity in adult Wistar rats. After purchase and acclimatization, the adult Wistar rats were weighed and divided into six equal groups (control and experimental groups). Thirty adult Wistar rats, which weighed between 150g to180g were used for this study. The rats were grouped into six groups (A, B, C, D, E and F), of five rats each. Group A (Control) was administered 1 ml dH2O/day. Group B (Al) was administered 100 mg/kg body weight (BW) of Al only. Group C (Al + CO1) was administered 250 mg/kg BW/day of aqueous CO seed extract and 100 mg/kg BW of Al. Group D (Al + CO2) was administered 500 mg/kg BW of aqueous CO seed extract and 100 mg/kg BW of Al. Group E (CO1) was administered 250 mg/kg BW of aqueous CO seed extract only. Group F (CO2) was administered 500 mg/kg BW of aqueous CO bark extract only. The administration, via an orogastric tube, lasted for 28 days and rats were fed with standard rat chow and had free access to water throughout the entire study period. At the end of the experiment, neurobehavioral activity (y maze test and NOR test) was evaluated, recorded. Results showed a significant decrease (P>0.05) in final body weight (FBW) of rats in the Al group when compared to the control and Al groups which showed an increase (P>0.05) in FBW. Comparison of neurobehavioral activity showed that rats in the Al group showed significant decrease (P>0.05) in neurobehavioral function compared to those in the Control and CO groups. Assessment of antioxidant activity showed increased (P>0.05) oxidative stress in the Al groups whereas the Control and CO groups showed significant increase (P>0.05) in antioxidant activity. Histological result showed that control group A retained their normal cerebellar architecture, Group treated with aluminium only showed multiple Neuropil vacuolation and degenerating pyramidal cells. Group C and Group D showed relatively normal pyramidal cell while Group E and Group F showed relatively normal pyramidal and neuroglial cells respectively. Conclusively, the findings showed that CO was not toxic to the animals but protected against Aluminium toxicity. The findings from this study provide the first research evidence on the protective activity of CO against aluminium induced neurotoxicity in adult Wistar rats.
