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.