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.

Human papillomavirus infection in head and neck cancer: The role of the secretory leukocyte protease inhibitor

“…This finding led us to investigate the role of SLPI in healthy mucosa of non-HNSCC patients and to correlate SLPI expression with smoking habits. In accordance with the data obtained in a rat model (18), we indeed showed that moderate/strong SLPI expression was mostly found in patients with smoking habits. In HNSCC, it is well documented that HPV-driven carcinogenesis occurs in younger patients when compared to patients with alcohol/tobacco-driven carcinogenesis (4,17).…”

“…In addition, Chan et al (18) showed that total neutrophil elastase concentration and activity as well as SLPI activity was increased following exposure to cigarette smoke. This finding led us to investigate the role of SLPI in healthy mucosa of non-HNSCC patients and to correlate SLPI expression with smoking habits.…”

“…Moreover, a recent report showed a positive correlation between cigarette smoke and SLPI-expression in a rat model (18). This finding motivated us to further study SLPI expression in healthy mucosal tissue of non-HNSCC patients and to correlate SLPI expression levels with smoking habits.…”

Therapeutic properties of green tea against environmental insults

“…Chan et al [57, 59] treated Sprague-Dawley rats with 2% Lung Chen Tea, a Chinese green tea, in the presence and absence of smoke for 56 days. Lung Chen Tea (2%) with the largest amount of EGCG was found to alter oxidative stress in the serum and lungs in the smoke-exposed group and protect against smoke-induced lung damage as determined by histological and morphometric analyses [57].…”

“…Lung Chen Tea (2%) with the largest amount of EGCG was found to alter oxidative stress in the serum and lungs in the smoke-exposed group and protect against smoke-induced lung damage as determined by histological and morphometric analyses [57]. Concomitantly, 2% Lung Chen Tea may also help to prevent the smoke-induced up-regulation of matrix metalloproteinase-12 (MMP12) activity, leading to a reduction in ROS [59]. Yang et al reported that catechins reduced oxidative stress by reducing the Bax/Bcl-2 ratio and preserving HSP70 chaperone protein expression in the lung of study animals [57].…”