Objective To observe the effect and mechanism of Shuji Decoction on muscular stiffness in Parkinson’s disease（ PD） model rats. Methods 24 PD model rats were induced by injection of 2 μl lactacystin（ 1 μg /μl） into substantia nigra region

then randomly assigned to model group and high

medium

low dose Chinese medicine group

with 6 rats in each group. Six rats injecting equivalent amount of normal saline were included in sham operation group as comparison. High

medium

low dose Chinese medicine group was given Shuji Decoction 40

20

10 g /（ kg·d） respectively by intragastric administration

while sham operation group and model group used saline20 g /（ kg·d） by intragastric administration. On Day 0

10

20

30

pole climbing tests were carried on for each group of rats separately and electromyography（ EMG） was used to record the electrophysiological change of PD rats’ common peroneal nerve. Immunohistochemical staining was used on day 30 to analyze the expression of tyrosine hydroxylase（ TH） positive cells in substantia nigra. Results Compared to sham operation group

model group had increased pole-climbing time and scores（ P < 0. 05） on day 10

20

30. Compared to the model group

all Chinese medicine groups had decreased pole-climbing time and scores measured on day 10

20

30（ P < 0. 05）. Compared with medium dose Chinese medicine group

high and low dose Chinese medicine group had increased pole-climbing time and scores on day 10

20

30（ P < 0. 05）. The differences of amplitude of distal or proximal muscle’s action potential

latency and motor nerve conduction velocity（ MCV） in model group and sham operation group had statistical significance（ P < 0. 05）. The differences of amplitude of distal or proximal muscle’ s action potential

latency and MCV in model group induced at each time point had statistical significance. On day 10

20

30

the differences of amplitude of distal or proximal muscle’s action potential

latency and MCV showed statistical significance（ P < 0. 05）comparing model group with all Chinese medicine groups. There were statistical significance（ P < 0. 05） on the differences of medium dose Chinese medicine group and high or low dose Chinese medicine group’s record of amplitude of distal or proximal muscle’s action potential

latency and MCV on day 10

20

30. Comparing with the sham operation group

the average optical density and positive area rate of TH positive cells in nigra region in the model group decreased significantly（ P < 0. 05）

while the average optical density and positive area rate in all Chinese medicine groups increased significantly（ P < 0. 05） comparing with the model group

in which

middle dosege Chinese medicine group showed the best effect（ P < 0. 05）. Conclusion Shuji Decoction can protect and repair dopaminergic neurons in PD model rats effectively and can release muscular stiffness

with best effect achieved at the dose of 20 g /（ kg·d）.