Objective::To investigate the neuroprotective effects of simvastatin on lipopolysaccharide(LPS)-indueed rat model of Parkinson’s disease(PD) and the mechanisms involved.Methods:Hemiparkinsonian rat models were induced by stereotaxieal injection of LPS in the right substantia nigra compacts.After 2 weeks of simvastatin treatment,rotational behavior test was performed after the intraperitoneal injection of apomorphine.Expression of tyroxine hydroxylase(TH) and glial fibrillan acidic protein were analyzed through immunohistochemical staining of substantia nigra and striatum,and the level of TNF-α was evaluated using enzyme-linked immunosorbent assay.Results:Comparing with untreated group,behavioral symptoms of the rats were significantly less in the rats that received simvastatin treatment.The TH positive cell count in substantia nigra and striatum were significantly increased(P<0.05) and TNF- α expression was significantly decreased(P<0.05) in simvastatin group compared to untreated group.Conclusions:Simvastatin could effectively inhibit the activation of astrocytes,reduce TNF-α expression,and exert anti-inflammatory effects,and thus protect the dopaminergic neurons in substantia nigra and striatum of the rat model of PD. Objective :: To investigate the neuroprotective effects of simvastatin on lipopolysaccharide (LPS) -indueed rat model of Parkinson’s disease (PD) and the mechanisms involved. Methods: Hemiparkinsonian rat models were induced by stereotaxieal injection of LPS in the right substantia nigra compacts. After 2 weeks of simvastatin treatment, rotational behavior test was performed after the intraperitoneal injection of apomorphine. Expression of tyroxine hydroxylase (TH) and glial fibrillan acidic protein were analyzed through immunohistochemical staining of substantia nigra and striatum, and the level of TNF-a was evaluated as using enzyme-linked immunosorbent assay. Results: Comparing with untreated group, behavioral symptoms of the rats were significantly less in the rats that received simvastatin treatment. The TH positive cell count in substantia nigra and striatum were significantly increased (P <0.05) and TNF - α expression was significantly decreased (P <0.05) in simvastatin group compared to untreated gr oup.Conclusions: Simvastatin could effectively inhibit the activation of astrocytes, reduce TNF-α expression, and exert anti-inflammatory effects, and thus protect the dopaminergic neurons in substantia nigra and striatum of the rat model of PD.