[The effect of ERK signaling pathway on cell apoptosis in airway smooth muscle cells of chronic asthmatic rats].
OBJECTIVE
To investigate the effect of ERK signaling pathway on apoptosis of airway smooth muscle cells (ASMCs) in chronic asthmatic rats.


METHODS
Thirty Wistar rats were assigned to two groups: control group (A group, n = 15)and chronic asthmatic group (B group, n = 15). The apoptosis of ASMCs were detected by Situ end labeling and Annexin-V FITC PI double staining. The expressions of bcl-2 and bax were detected by immunocytochemical staining. The levels of caspase-3 protein were detected by Western blot. ASMC were treated with ERK activator epidermal growth factor (EGF) and inhibitor PD98059.


RESULTS
Compared with control group, the apoptotic index and the percentage of the early apoptotic cells in ASMC from chronic asthmatic group were significantly decreased. After treatment with PD98059, the apoptotic index, the percentage of the early apoptotic cells, the expression of bax and the expression of caspase-3 protein in ASMC from chronic asthmatic group were significantly increased, and the expression of bcl-2 in ASMC from chronic asthmatic group were significantly decreased. Compared with those before treatment, apoptotic index and the percentage of the early apoptotic cells were significantly increased in EGF-treated cells. PD98059 could markedly inhibit the effect of EGF.


CONCLUSIONS
Apoptotic activation is significantly decreased in ASMC from chronic asthmatic group while the endogenous proliferation activation is significantly increased. The regulation of cell apoptosis is possibly related to ERK signaling pathway. The bcl-2 family and caspase-3 may participate in the regulation mechanism of cell apoptosis by ERK signaling pathway in ASMC from chronic asthmatic group.
Bai
Jing
J
Department of Respiratory Medicine, Tongji Hospital Affiliated to Tongji Medical College, Huazhong University of Sciences and Technology, Wuhan 430030, China.
Liu
Xian-sheng
XS
Xu
Yong-jian
YJ
Zhang
Zhen-xiang
ZX
Xie
Min
M
Ni
Wang
W
D000818:Animals; D017209:Apoptosis; D001249:Asthma / Q000201:enzymology* / Q000503:physiopathology*; D004195:Disease Models, Animal; D048049:Extracellular Signal-Regulated MAP Kinases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D020935:MAP Kinase Signaling System; D008297:Male; D032389:Myocytes, Smooth Muscle / Q000201:enzymology*; D051381:Rats; D017208:Rats, Wistar; D012137:Respiratory System / Q000166:cytology* / Q000201:enzymology
D048049:Extracellular Signal-Regulated MAP Kinases