title: [Effect of insulin-like growth factor-1 on hyperoxia-induced apoptosis in A549 cells].
abstract: OBJECTIVE
  To investigate the effect of insulin-like growth factor-1 (IGF-1), which can promote cell differentiation and inhibit cell apoptosis, on hyperoxia-induced apoptosis in A549 cells and its anti-apoptotic mechanism.
  
  
  METHODS
  A549 cells were sub-cultured, exposed to hyperoxic conditions and were then treated with different concentrations of IGF-1 (1, 10, and 100 ng/mL) for 48 hours. Cell viability was measured by MTT assay. Cell apoptosis was evaluated by Annexin V-FITC/PI double-staining flow cytometry. Expression levels of Bax and Bcl-2 were measured by flow cytometry.
  
  
  RESULTS
  The middle-dose and high-dose IGF-1 intervention groups had higher cell viabilities than the hyperoxic exposure group [(64±3)% and (88±4)% vs (51±3)%; P<0.05]. Compared with the air control group, the hyperoxic exposure group had a significantly higher apoptotic rate [(38.3±5.4)% vs (2.4±0.9)%; P<0.05], a significantly lower expression level of Bcl-2 [(72±5)% vs (91±4)%; P<0.05], and a significantly higher expression level of Bax [(54±6)% vs (3±2)%; P<0.05]. Compared with the hyperoxic exposure group, the low-dose, middle-dose, and high-dose IGF-1 intervention groups had significantly lower apoptotic rates [(16.1±4.7)%, (9.2±2.8)%, and (6.9±2.5)% vs (38.3±5.4)%; P<0.05], significantly higher expression level of Bcl-2 [(79±4)%, (94±4)%, and (100±5)% vs (72±5)%; P<0.05], and significantly lower expression level of Bax [(26±4)%, （5±2)%, and (4±2)% vs (54±6)%; P<0.05].
  
  
  CONCLUSIONS
  Hyperoxia significantly inhibits proliferation and promotes apoptosis in A549 cells. IGF-1 may promote cell proliferation and inhibit hyperoxia-induced apoptosis in A549 cells by regulating the expression of Bcl-2 and Bax.
authors.affiliation: Department of Pediatrics, Yanbian University Hospital, Yanji, Jilin, China. kimzhenai1103@yahoo.com.cn
authors.forename: Zhen-Ai
authors.initials: ZA
authors.lastname: Jin
authors.forename: Yi-Kun
authors.initials: YK
authors.lastname: Zhao
authors.forename: Zheng-Yong
authors.initials: ZY
authors.lastname: Jin
authors.forename: Hai-Feng
authors.initials: HF
authors.lastname: Qi
authors.forename: Mokhles Wali
authors.initials: MW
authors.lastname: Gul
authors.forename: Ming-Hua
authors.initials: MH
authors.lastname: Gong
mesh_terms: D017209:Apoptosis / Q000187:drug effects*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D018496:Hyperoxia / Q000473:pathology*; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000032:analysis; D051028:bcl-2-Associated X Protein / Q000032:analysis
chemical_list: C494826:BAX protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D007334:Insulin-Like Growth Factor I