Morphological Changes of Mesencephalic Dopaminergic Neurons by Chronic Administration of Aluminium in Rats

Objective] To study the neurotoxic effect of aluminium on dopaminergic neurons in rat mesencephalon and the correlation between the damage to DA neurons and the impairment of rat cognition. [Methods] The chronic aluminium intoxicated models were set up by adding aluminium chloride into tap water(1 600 mg/L,ad libitum)and treated for 90 days,the short-term learning and memory ability of rats were evaluated by dark-avoiding test,Nissl's staining method and silver staining method were used to detect the pathological changes in rat brain,the DA neurons in ventral tegmental area and substantia nigra were labeled using immunohistochemical method,the neuron numbers were scored by utilizing the image analysis system. [Results] Compared with the control,the foot shock time increased sharply(P0.01) and the latent period shortened(P0.001)in aluminium intoxicated rats,and the loss of dopaminergic neurons in ventral tegmental area and substantia nigra were detected in the coronal brain sections at five levels(P0.05),some abnormal DA neurons were also found. [Conclusion] Aluminium has striking toxic effect on mesencephalic DA neurons and the impairment of DA neurons might be correlated with the disfunction of cognition in rats administered aluminium.