title: Inhibitory effect of Chinese green tea on cigarette smoke-induced up-regulation of airway neutrophil elastase and matrix metalloproteinase-12 via antioxidant activity.
abstract: Our recent study has indicated that Chinese green tea (Lung Chen), in which epigallocatechin-3-gallate (EGCG) accounts for 60% of catechins, protected cigarette smoke-induced lung injury. We now hypothesized that Lung Chen tea may also have potential effect on lung oxidative stress and proteases/anti-proteases in a smoking rat model. Sprague-Dawley rats were exposed to either sham air (SA) or 4% cigarette smoke (CS) plus 2% Lung Chen tea or water by oral gavage. Serine proteases, matrix metalloproteinases (MMPs) and their respective endogenous inhibitors were determined in bronchoalveolar lavage (BAL) and lung tissues by gelatin/casein zymography and biochemical assays. Green tea consumption significantly decreased CS-induced elevation of lung lipid peroxidation marker, malondialdehyde (MDA), and CS-induced up-regulation of neutrophil elastase (NE) concentration and activity along with that of α(1)-antitrypsin (α(1)-AT) and secretory leukoproteinase inhibitor (SLPI) in BAL and lung. In parallel, significant elevation of MMP-12 activity was found in BAL and lung of the CS-exposed group, which returned to the levels of SA-exposed group after green tea consumption but not CS-induced reduction of tissue inhibitor of metalloproteinase (TIMP)-1 activity, which was not reversed by green tea consumption. Taken together, our data supported the presence of local oxidative stress and protease/anti-protease imbalance in the airways after CS exposure, which might be alleviated by green tea consumption through its biological antioxidant activity.
authors.affiliation: Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Ka Ho
authors.initials: KH
authors.lastname: Chan
authors.forename: Stanley Chi Hang
authors.initials: SC
authors.lastname: Chan
authors.forename: Sze Chun
authors.initials: SC
authors.lastname: Yeung
authors.forename: Ricky Ying Keung
authors.initials: RY
authors.lastname: Man
authors.forename: Mary Sau Man
authors.initials: MS
authors.lastname: Ip
authors.forename: Judith Choi Wo
authors.initials: JC
authors.lastname: Mak
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D002681:China; D004195:Disease Models, Animal; D019272:Leukocyte Elastase / Q000032:analysis / Q000378:metabolism*; D008168:Lung / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D053508:Matrix Metalloproteinase 12 / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D012907:Smoking / Q000009:adverse effects*; D013662:Tea; D062789:Tobacco Products / Q000009:adverse effects; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D000975:Antioxidants; D013662:Tea; D008315:Malondialdehyde; D019272:Leukocyte Elastase; D053508:Matrix Metalloproteinase 12