Neuroprotective potential of Aloe arborescens against copper induced neurobehavioral features of Parkinson's disease in rat.

Copper (Cu) is an important trace element for the organism survival, which ensures the normal functioning of different biosystems. However, excessive levels of this heavy metal are responsible for profound physiological alterations including the central nervous system. Numerous findings sustain the involvement of heavy metals, as an environmental risk factor such as copper (Cu), in the neuropathology of Parkinson's disease (PD) which is a chronic neurodegenerative disorder that principally affects the motor system. The classic and evident symptoms of PD namely rigidity, tardiness of movement, and difficulty with walking, result from progressive dopaminergic neurons death within substantia nigra. Whereas, few pharmacological trials have shown a beneficial role against Cu neurotoxicity, Aloe arborescens is one of the powerful medicinal plants with an array of therapeutic effects. Thus, we aimed through the present study, to evaluate the impact of acute Cu intoxication (10μg/g B.W. i.p) for 3days on the dopaminergic system and locomotor performance, together with the possible restorative effect of oral administration of aqueous extract of Aloe arborescens gel (AEAAG) (200mg/kg B.W.). By means of immunohistochemistry, we noted, in the Cu intoxicated rats, a significant loss of TH (tyrosine hydroxylase) expression within substantia nigra compacta (SNc), ventral tegmental area (VTA) and the subsequent striatal outputs, those alterations were correlated to behavioral abnormalities such as a severe drop of locomotor performance. While AEAAG administration to Cu intoxicated rats showed a noticeable beneficial effect; this potential was featured by a complete recovery of the TH expression and locomotor behavior deficiencies in the intoxicated rats. The present investigation have brought, on the one hand, an experimental evidence of an altered dopaminergic innervations following Cu intoxication and on the other hand, a new pharmacological property of Aloe arborescens that may be used as a neuroprotective plant for neurodegenerative disorders, such as PD, touching the dopaminergic system trigged by heavy metals.