Objective To observe the effect of fire-needle stimulation of "Neixiyan"(EX-LE4) and "Dubi"(ST35) on changes of motor function

structure of cartilage degradation and inflammatory factors in knee osteoarthritis(KOA) rats

so as to explore its underlying mechanisms in improving KOA. Methods Thirty-nine male SD rats were randomly divided into normal

model and fire-needle groups(n=13 in each group). The KOA model was established by injection of Monoiodoacetate(MIA

1 mg) into the lumen of the right knee joint. On the 7

(th)

day after successful modeling

fire-needle was applied to EX-LE4 and ST35

twice a week for 3 weeks. The rats' behavioral reactions of gait(0 to 3 points) and claw pressure(0 to 3 points) were scored

and histopathological changes scored by assessing the impairment grade(0 to 6) and stage(0 to 4) of the articular cartilage after safranin O-fast green staining. The contents of serum Interleukin(IL)-1α

Tumor necrosis factor α(TNF-α)

IL-10

IL-37 and transforming growth factor β(TGF-β) were assayed by ELISA

and ultrastructural changes were observed under transmission electron microscope(TEM). Results After modeling

the gait and claw-pressure scores were significantly increased in the model group in comparison with the normal group(P

<

0.05)

and the OA score and contents of serum IL-1α and TNF-α were also appa-rently increased in the model group relevant to the normal group(P

<

0.05

P

<

0.01)

while the levels of serum IL-10

IL-37 and TGF-β remarkably decreased in the model group in contrast to the normal group(P

<

0.01). After the intervention

the increase of gait and claw-pressure and OA scores

as well as serum IL-1α and TNF-α contents

and the decrease of serum IL-10

IL-37 and TGF-β levels were all reversed in the fire needle group(P

<

0.05

P

<

0.01). Outcomes of TEM showed more and larger lipid droplets

swollen mitochondria with some vacuoles

and expanded

broken or dissolved rough endoplasmic reticulum in the model group

which was milder in the fire-needle group. Conclusion Fire-needle can improve motor function and relieve impairment of articular cartilage of KOA rats

which may be related to its effects in reducing inflammatory factors and in increasing anti-inflammatory factor levels.