Objective To observe the influence of electroacupuncture(EA) of "Fengfu"(GV16) and "Taichong"(LR3) on morphological changes and apoptotic percentage of substantia nigra cells so as to explore its underlying mechanism in relieving Parkinson's disease.Methods Forty Wistar rats were randomly divided into normal control

sham-operation(sham)

model and EA groups

with 10 rats in each.The Parkinson's disease model was established by micro-injection of 6-hydroxyl-dopamine(6-OHDA) into the right striatum.EA(2Hz

1mA) was applied to "Fengfu"(GV16) and "Taichong"(LR3) for 30 min

once daily for 2 weeks.HE staining

Nissl staining and immunohistochemical staining were conducted for observing the morphological changes of substantia nigra pars compacta(SNc) and striatum

and the tyrosine hydroxylase(TH) immuno-reaction(IR) positive neurons and nerve fibers.The apoptosis was detected by flow cytometry.Results Compared to the normal control and sham groups

the total number of TH-IR positive neurons and Nissl-stained cells

and OD value of TH-IR positive nerve fibers in the SNc on the 6-OHDA-lesioned side were significantly lower in the model group(P<0.01).Compared with the model group

the aforementioned 3 indexes of the EA group were increased obviously(P<0.01).The percentage of apoptosis of SNc on the 6-OHDA-lesioned side was obviously lower in the EA group than in the model group(P<0.01)

but still obviously higher than in the normal group and sham group(P<0.01).Conclusion Electroacupuncture therapy can significantly increase the number of neurons of substantia nigra and the density of striatum nerve fibers

and reduce the apoptotic percentage of substantia nigra cells in the Parkinsonian rats

which may contribute to its effect in relieving Parkinson's disease.