[Effects of electroacupuncture intervention on expression of pulmonary metalloproteinase-9 and tissue inhibitor-1 proteins in rats with chronic obstructive pulmonary disease].

Objective: To observe the effect of electroacupuncture (EA) stimulation on the expression of metalloprotei- nase-9 (MMP-9) and tissue inhibitor-1 (TIMP-1) in the lung tissue in rats with chronic obstructive pulmonary disease (COPD), so as to reveal its mechanisms in protecting the lung tissue.
Methods: Forty male SD rats were equally randomized into control, model, medication and EA groups. The COPD model was established by smoke-fumigation method (passive smoking in a closed box) and endotracheal injection of lipopolysaccharide (200 microg/100 microL) for 30 days. Rats of the medication group were treated by i.p. of dexamethasone acetate injection (2.0 mg/kg), once daily for 22 days. EA was applied to LU 9, ST 36, ST 40 and KI 3 for 20 min, once daily for 22 days. Pathological changes of the pulmonary tissue were observed under optical microscope after hematoxylin and eosin (H.E.) staining. The expression of pulmonary MMP-9 and TIMP-1 was assayed by immunohistochemistry.
Results: H.E. staining showed pulmonary diffuse edema, severe inflammatory cell infiltration, and increase of the numbers of goblet cells, proliferation of fibroblasts, etc. in the model group which were relatively milder in the medication and EA groups. The expression levels of pulmonary MMP-9 and TIMP-1 proteins were significantly higher in the model group than in the control group (P<0.05), and were considerably down-regulated in both EA and medication groups in comparison with the model group (P<0.05). There were no significant differences between the EA and medication groups in MMP-9 and TIMP-1 expression levels (P>0.05).
Conclusion: EA can effectively suppress the increased expression of pulmonary MMP-9 and TIMP-1 in COPD rats, which may contribute to its effect in improving COPD-induced pathological changes.