Objective To observe the effect of catgut implantation at "Yingxiang"(LI20) on lower airway remodeling and levels of osteopon-tin(OPN) protein in allergic rhinitis(AR) rats

so as to reveal its mechanisms underlying improvement of AR. Methods Male SD rats were randomly divided into control

model and catgut implantation groups

with 10 rats in each group. The AR model was established by intraperitoneal injection and nasal drip of ovalbumin. The catgut implantation was applied to bilateral "Yingxiang"(LI20) for 28 days in rats of the catgut implantation group. The total score of allergic symptoms of rats in each group were observed. The histopathological changes of lower airway were observed under light microscope after Hematoxylineosin

Periodic acid-Schiff and Masson staining. The expression of OPN protein was detected by immunohistochemistry and Western blot

separately. Results The total score of allergic symptoms of nose-wiping

running nose and sneezing

count of lung goblet cells

lung fiber content

and immunoactivity and expression levels of OPN protein were significantly increased in the model group in contrast to the control group(P<0.05). After the intervention

the total score of allergic symptoms

count of lung goblet cells

immunoactivity and expression levels of OPN protein were considerably down-regulated in the catgut implantation group relevant to the model group(P<0.05). H.E. stain showed thickening of partial airway wall

narrowing of lumen

increase of mucus section

widened alveolar septum

infiltration of inflammatory cells

lymphocytes and eosinophil around the bronchus and in the lung interstitium in AR rats

which was milder in the catgut implantation group. The immunoactivity and expression levels of OPN protein were positively related with the lung goblet cells count and lung fiber content(P<0.05

P<0.01). Conclusion Acupoint implantation of catgut can improve pathological changes of lower airway remodeling

which may be related to its effect in down-regulating the expression of OPN protein in the lung tissue.