Inhibitory effect of Chinese green tea on cigarette smoke-induced up-regulation of airway neutrophil elastase and matrix metalloproteinase-12 via antioxidant activity

Free Radic Res. 2012 Sep;46(9):1123-9. doi: 10.3109/10715762.2012.692786. Epub 2012 Jun 8.

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology*
  • China
  • Disease Models, Animal
  • Leukocyte Elastase / analysis
  • Leukocyte Elastase / metabolism*
  • Lung / drug effects
  • Lung / enzymology
  • Lung / metabolism*
  • Male
  • Malondialdehyde / metabolism
  • Matrix Metalloproteinase 12 / metabolism*
  • Rats
  • Rats, Sprague-Dawley
  • Smoking / adverse effects*
  • Tea*
  • Tobacco Products / adverse effects
  • Up-Regulation / drug effects

Substances

  • Antioxidants
  • Tea
  • Malondialdehyde
  • Leukocyte Elastase
  • Matrix Metalloproteinase 12