by Ka H Chan, Judith CW Mak, et al.
June 28, 2009
Background: Epigallocatechin-3-gallate (EGCG), which has been shown to have potent antioxidant effect, comprises 80% of catechins in Chinese green tea. This study was to investigate whether cigarette smoke (CS) exposure would induce lung morphological changes and oxidative stress in the cigarette smoke-exposed rat model, and whether Chinese green tea (Lung Chen tea with EGCG as its main active ingredient) consumption would alter oxidative stress in sera and lung leading to protection of cigarette smoke -induced lung damage.
Methods: Sprague-Dawley rats were randomly divided into four groups, i.e.:
• Sham air (SA)
• 4% cigarette smoke,
• 2% Lung Chen tea plus sham air, or
• 4% cigarette smoke.
Exposure to sham air or 4% cigarette smoke was performed for 1h/day for 56 days in ventilated smoking chambers. Sera [blood] and lung tissues were collected 24h after last cigarette smoke exposure for histology and all biochemical assays.
Results:
• Airspace enlargement and goblet cell hyperplasia were observed after 56-day cigarette smoke exposure alone,
• Which were abolished in the presence of green tea consumption.
• Serum 8-isoprostane level was significantly elevated (p<0.01) as well as lung superoxide dismutase (SOD) and catalase activities in cigarette smoke exposed rats compared to sham air-exposed rats (p<0.05),
• Which returned to the levels of sham air-exposed rats after Chinese green tea consumption.
Conclusion: These results indicate that:
• Increased levels of systemic oxidative stress after cigarette smoke exposure play an important role in the induction of lung damage.
• Chinese green tea may have the ability to suppress cigarette smoke-induced oxidative stress that leads to protection of lung injury.
Source: Respiratory Medicine, May 30. PMID: 19487113, by Chan KH, Ho SP, Yeung SC, So WH, Cho CH, Koo MW, Lam WK, Ip MS, Man RY, Mak JC. Departments of Medicine and Pharmacology, University of Hong Kong; Department of Pharmacology, Chinese University of Hong Kong, China. [E-mail: judithmak@hkucc.hku.hk]
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