Parkinsons disease (PD) is the second most neurodegenerative disease.Though the pathology of PD is clear,the pathogenesis of PD is still unkown.Recent evidences have shown that inflanunatory changes are also involved in the progressive loss of dopaminergic neurons that result in PD.We used lipopolysaccharide (LPS) injected into the substantia nigra pars compacta (SNc) of rat to investigate the underlied pathogenesis of PD.Our study showed that lipopolysaccharide injection dose-dependently caused dopaminergic neuron loss in SN.Significant alteration of apomorphine induce rotation was observed in LPS lesioned rats.We found that the expression of tyrosine hydroxylase were decreased in SN and striatum,while the expression of COX-2 were upregulated.We also examined the expression of malonaldehyde which was dose-dependently increased in SN and striatum but not in cortex and hippocampus.The in vivo experiments suggested that in the inflammatory model of PD,oxidative stress may have an interative role with inflammation.