Abstract: Objective To survey the regularities of dopamine neurons in substantia nigra(SN) of middle brain with age increasing and further provide objective evidence for revealing lesion of substantia nigra.Methods Nineteen normal individuals were divided into young(17 to 35 years old),middle-aged(40 to 59 years old),and aged(60 to 84 years old) groups.The age-related changes of neuromelanin(NM) containing and tyrosine hydroxylase(TH) immunoreactive cell number of SN were analyzed.Results Stereological counting based on Nissl stain and TH immunoreactivity revealed that,both Nissl stained and neuromelanin containing neurons decreased in the process of ageing,while the decrease of both TH immunoreactive and NM containing cell number was the most significant changes.Conclusion NM may participate in ageing influenced degeneration and loss of dopaminergic neurons.And that may serve as the foundation of neurodegenerative disease.

Key words: substantia nigra, immunohistochemistry, stereology, tyroxine hydroxylase