Immunohistochemical detection of apoptotic proteins, p53/Bax and JNK/FasL cascade, in the lung of rats exposed to cigarette smoke.
Lung disease is the leading and second-leading cause of death in women and men in Taiwan, respectively. Epidemiological studies conducted in Taiwan have shown that cigarette smoking is the principal risk factor of lung disease, but little is known about the association between apoptosis and cigarette smoke (CS)-induced lung pathogenesis. We designed an animal exposure system to study signal proteins involved in the process of apoptosis induced by smoking in rat terminal bronchiole. Rats were exposed to CS in doses of 5, 10, and 15 cigarettes, respectively, and the exposure lasted for 30 min, twice a day, 6 days a week for 1 month. Following which the rats were sacrificed and the lung tissues were analyzed by histopathological methods. The terminal bronchioles revealed mild to severe inflammation according to the doses of CS and marked lipid peroxidation, lymphocyte infiltration, congestion, and epithelial emphysema of alveolar spaces were also noted. Using an in situ cell death detection kit (TA300), the association of CS with apoptosis was determined in a concentration-dependent manner. Immunohistochemical evaluation showed that CS treatment produced an increase in the cellular levels of Bax, t-Bid, cleaved caspase-3, phospho-p53, phospho-JNK, and FasL but a decline in Bcl-2 and Mcl-1 (p<0.001 for all) in rat terminal bronchioles. The results provided evidences suggesting that exposure to CS not only induced apoptosis, but also involved p53/Bax and JNK/FasL cascade pathway.
Wu
Cheng-Hsun
CH
Department of Anatomy, China Medical University, Taichung, Taiwan.
Lin
Hui-Hsuan
HH
Yan
Fu-Pin
FP
Wu
Cheng-Hua
CH
Wang
Chau-Jong
CJ
D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D001980:Bronchi / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D004305:Dose-Response Relationship, Drug; D053222:Fas Ligand Protein; D007124:Immunoenzyme Techniques; D019570:Inhalation Exposure; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism*; D008297:Male; D008562:Membrane Glycoproteins / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D012906:Smoke / Q000009:adverse effects*; D014026:Nicotiana; D048069:Tumor Necrosis Factors / Q000378:metabolism*; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D051028:bcl-2-Associated X Protein / Q000378:metabolism*
D053222:Fas Ligand Protein; C505662:Faslg protein, rat; D008562:Membrane Glycoproteins; D012906:Smoke; D048069:Tumor Necrosis Factors; D016159:Tumor Suppressor Protein p53; D051028:bcl-2-Associated X Protein; D048031:JNK Mitogen-Activated Protein Kinases