Abstract: Objective To study the degeneration of dopaminergic neurons and the relationship between it and the level of TNF-α in serum by intranigral injection of LPS. Methods LPS or PBS was stereotaxically injected into substantia nigra(SN).At different survival times,the damage to the substantia nigral DA neurons was observed by using tyrosine-hydroxylase immunohistochemical staining and the level of TNF-α in serum was measured by Radioimmunoassay. Results 24 hours after LPS injection,there was apparent reduction in TH-positive cells on the LPS-injected side.The decrease reached a peak after 14 days.In the subsequent days,the degree of degeneration remained at the stage. Differences were observable when compared the level of TNF-α in serum of 24h、14d、28d with that of the PBS group.The former was higher. The study revealed linear correlation between the level of TNF-α and the survival rate (percentage of right TH-positive neurons to left). Conclusion The degeneration of TH-positive neurons induced by inflammation was in time-dependent manner. While in development of PD the effect of inflammatory damage was only early stage；In PD local inflammation in substantia nigra may be induce systemic inflammatory reaction; The level of TNF-α in serum is related to the degeneration of TH-positive neurons in substantia nigra.

Key words: Parkinson Disease, Lipopolysaccharide, dopaminergic neuron, tumour necrosis factor-α, inflammation