Ethanolic Leaf Extract of Aloe Barbadensis (Aloe Vera) Mitigates Mercury Induced Alzheimer –Like Symptoms on Basal Ganglia of Albino Wistar Rats

Abstract

Mercury exposure has been linked with numerous neurological disorders that frequently trigger Alzheimer’s disease through oxidative stress processes. This study aims to determine the ameliorative potential of Aloe barbadensis on mercury induced Alzheimer- like symptoms on basal ganglia of wistar rats. Thirty-five wistar rats with average weight 150g were randomly divided into five groups designated A-E with seven rats per group. Group A served as the control and did not receive any treatment, group B received 5mg/kg mercury chloride only for three weeks, group C received 500mg/kg of ethanolic extract of Aloe barbadensis for 3 weeks, groups D and E received 5mg/kg of mercury chloride for 3 weeks followed by 250mg/kg and 500mg/kg of ethanolic extract of Aloe barbadensis for 3 weeks respectively. All administrations were via oral gavage. Anxiety index and recognition memory were evaluated using open field and novel object recognition tests. Blood was obtained via ocular puncture for serum estimation of superoxide dismutase (SOD), malondialdehyde (MDA) levels. Brain tissue obtained were homogenized for estimation of Acetylcholinesterase (AChE) and glutamate levels and also processed for routine Hematoxylin and eosin and silver Beilschowsky staining. Results of the neurobehavioural tests showed significant (P<0.05) increase in anxiety indexwhen comparand significant decrease (P<0.05) in recognition index in group B. There was significant (P<0.05) decrease in SOD, AChE, glutamatelevels in group B compared with groups A, C, D and E while there was a significant increase (P<0.05) in MDA levels in group B. Histological study of the basal ganglia showed pyknotic nuclei in group B while silver beilschowsky stain revealed amyloid plaques deposition in group B. These results revealed that mercury chloride caused oxidative stress, anxiety, reduced AChE and glutamate levels, pyknosis and deposition of amyloid plaques on the basal ganglia and Aloe Barbadensis ethanolic extract mitigated these effects and may be useful in the management of Alzheimer –like symptoms.