Chinese green tea ameliorates lung injury in cigarette smoke-exposed rats
Received 13 December 2008; accepted 28 April 2009. published online 01 June 2009.
Summary
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 CS-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 CS-induced lung damage.
Methods
Sprague-Dawley rats were randomly divided into four groups, i.e. sham air (SA), 4% CS, 2% Lung Chen tea plus SA or 4% CS. Exposure to SA or 4% CS was performed for 1h/day for 56 days in ventilated smoking chambers. Sera and lung tissues were collected 24h after last CS exposure for histology and all biochemical assays.
Results
Airspace enlargement and goblet cell hyperplasia were observed after 56-day CS 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 CS-exposed rats compared to SA-exposed rats (p<0.05), which returned to the levels of SA-exposed rats after Chinese green tea consumption.
Conclusion
These results indicate that increased levels of systemic oxidative stress after CS exposure play an important role in the induction of lung damage. Chinese green tea may have the ability to suppress CS-induced oxidative stress that leads to protection of lung injury.
aDepartment of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
bDepartment of Pharmacology, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
cDepartment of Pharmacology, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong SAR, China
dResearch Centre of Heart, Brain, Hormone and Healthy Aging, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China
Corresponding author. Division of Respiratory and Critical Care Medicine, Department of Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Room 804, Administration Block, Pokfulam Road, Hong Kong SAR, China. Tel.: +852 28555886; fax: +852 28186474.
ABSTRACT