Objective To observe the influence of electroacupuncture(EA) therapy on the expression of tyrosine hydroxylase(TH) and cyclooxygenase-2(COX-2) proteins of Substantia Nigra cells(SNc) in the rotenone-induced Parkinson's disease(PD) rats

so as to explore the mechanism of EA underlying improvement of PD.Methods Forty rats were randomly divided into normal

sham-operation(sham)

model and EA groups(n=10/group).The PD model was established by successive subcutaneous injection of rotenone(highly selective lesions of nigrostriatal dopaminergic neurons) for 28 days.EA(2 Hz

1 mA) was applied to bilateral "Fengfu"(GV 16) and "Taichong"(LR 3) for 20 min

once daily for 14 days.The expression levels of TH and COX-2 proteins in the Substantia Nigra of midbrain were detected with Western blotting.Results Compared with the normal group

the expression level of TH protein in the model group was significantly decreased(P<0.01)

and that of COX-2 protein in the model group was significantly increased(P<0.01).After the EA treatment

the expression level of TH in the EA group was obviously upregulated(P<0.01)

and that of COX-2 protein in the EA group was considerably down-regulated(P<0.01).No significant differences were found between the normal and sham groups in the expression levels of TH and COX-2 proteins(P>0.05).Conclusion EA therapy can decrease inflammation mediator COX-2 protein expression and upregulate TH protein expression in the Substantia Nigra of midbrain in PD rats

which may contribute to its effect in relieving PD in clinic.