Objective      To determine the efficiency of Fuyuan capsule (Fyc

a capsule containing several Chinese herbs) on the expression

of urokinase-type plasminogen activator (uPA)

uPA receptor (uPAR)

plasminogen activator inhibitor (PAI) and NF-κB in the cartilage tissues of experimental osteoarthritis (OA) rabbits.       Methods      A total of 48 New Zealand rabbits were divided into 6 groups randomly with 8 rabbits in each group: normal group

model group

glucosamine hydrochloride capsule group [90 mg/(kg·d)

]

and low-

middle- and high-dose Fyc capsule groups [1 350

2 700 and 5 400 mg/(kg·d)

]

. The rabbits of model and treatment groups were inflicted by combined injection of D-galactose and plaster immobilization into their left knee joint to produce osteoarthritis model. All drugs were given from the same day of modeling

by gavage injection

daily

for 10 weeks. Mankin’s score was detected by light microscopy and HE staining. Then cartilage sections were analyzed by immunohistochemistry for uPA

uPAR and PAI. The protein expressions of uPA and NF-κB were detected by Western blotting.       Results      After treatment with high-dose Fyc and glucosamine hydrochloride capsule

the Mankin’s score was decreased significantly when compared with model group (3.28±0.46 and 3.46±0.78

vs

8.73±0.94

P

<

0.01). Immunohistochemical staining indicated that the expression intensities and positive cell ratio of uPA and uPAR were decreased and those of PAI were increased

and Western blotting showed that the protein expressions of uPA and NF-κB were reduced significantly in high-dose Fyc and glucosamine hydrochloride capsule groups. Compared to the model group

all these difference were significantly (

P

<

0.01). But there was no significant difference in the inhibiting effect to uPA in the high-dose Fyc and glucosamine hydrochloride groups (

P

>0.05)

but the former group showed stronger effect on NF-κB reduction (

P

<

0.05).       Conclusion      Fyc capsule downregulates uPA

uPAR and NF-κB

while upregulate PAI in the cartilage tissues of experimental osteoarthritis rabbits

which suggests the capsule

may exert its effect through regulating the uPA system and NF-κB signaling pathway.