[Effect of tea polyphenols on oxidative damage and apoptosis in human bronchial epithelial cells induced by low-dose cigarette smoke condensate].
OBJECTIVE
To determine the effect of tea polyphenols on oxidative damage and apoptosis in human bronchial epithelial cells induced by low-dose cigarette smoke condensate (CSC).


METHODS
We prepared CSC. 3-(4,5-dimethyl thiazoly) 2,5-diphenyl-tetrazoliun bromide (MTT) assay was used to determine the growth of cultured human bronchial epithelial cells (HBE135-E6E7). Fluorescent-chemiluminescent analyzer was used to measure cell reactive oxygen species (ROS) level. DNA ladder method was used to detect HBE135-E6E7 apoptosis. Reverse transcription-polymerase chain reaction (RT-PCR) was used to detect Bcl-2 and Bax mRNA expression.


RESULTS
Concentration of intracellular ROS in the CSC group and CSC + TP group was significantly higher than that in the control group (P<0.01); concentration of intracellular ROS in the CSC + TP group was significantly lower than that in the CSC group (P<0.01). Apparent DNA breakage of the tail belt appeared in the CSC Group,while only a small amount of DNA breakage of the tail belt appeared in the CSC + TP group. Compared with the control group, Bcl-2 mRNA expression was reduced and Bax mRNA expression was increased in the CSC group (all P<0.01). Compared with the CSC group, Bcl-2 mRNA expression was increased and Bax mRNA expression was reduced in the CSC+TP group (all P<0.01). Ratio of Bcl-2 mRNA/ Bax mRNA in the CSC group and CSC+TP group was significantly lower than that in the control group (all P<0.01).


CONCLUSIONS
TP can antagonize CSC-induced airway epithelial cell apoptosis through the effective removal of ROS, promoting Bcl-2 mRNA expression and inhibiting the expression of Bax mRNA.
Qing
Chunhua
C
Department of Respiratory Diseases, Second Xiangya Hospotal, Central South University, Changsha 410011, China.
Chen
Ping
P
Xiang
Xudong
X
D017209:Apoptosis / Q000187:drug effects*; D001980:Bronchi / Q000166:cytology*; D002460:Cell Line; D004847:Epithelial Cells / Q000166:cytology; D005419:Flavonoids / Q000302:isolation & purification / Q000494:pharmacology*; D006801:Humans; D018384:Oxidative Stress; D010636:Phenols / Q000302:isolation & purification / Q000494:pharmacology*; D059808:Polyphenols; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012906:Smoke / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects; D013662:Tea / Q000737:chemistry; D014026:Nicotiana; D051028:bcl-2-Associated X Protein / Q000378:metabolism
C494826:BAX protein, human; D005419:Flavonoids; D010636:Phenols; D059808:Polyphenols; D019253:Proto-Oncogene Proteins c-bcl-2; D012906:Smoke; D013662:Tea; D051028:bcl-2-Associated X Protein