[Lipopolysaccharide and hyperoxia induce nuclear factor-kappa B expression in human embryo lung fibroblasts in vitro].

OBJECTIVE

The development of bronchopulmonary dysplasia (BPD) is attributed to intrauterine inflammatory and postnatal mechanical ventilation and hyperoxia. The present study was aimed to investigate the effects of lipopolysaccharide (LPS) and hyperoxia exposure on the nuclear factor-kappa B (NF-kappaB) expression in human embryo lung fibroblasts (HELFs) in vitro.

METHODS

Either LPS (100 ng/mL) or hyperoxia (60%), or a combination of both was employed to stimulate confluent HELFs. After 0.5, 1, 2 and 4 hrs of stimulation, the nuclear translocation of two subunits p50 and p65 in HELFs was detected with immunocytochemistry. Reverse transcription quantitative polymerase chain reaction (RT-PCR) was used to measure mRNA expression of NF-kappaB p50 and p65.

RESULTS

LPS or hyperoxia stimulation induced the nuclear translocation of p50 and p65 at 30 minutes of exposure. mRNA expression of NF-kappaB p50 and p65 peaked at 1 hr and then gradually decreased. A stimulation of LPS combined with hyperoxia induced the nuclear translocation of p50 and p65. NF-kappaB p50 and p65 mRNA expression peaked at 2 hrs of stimulation and then decreased slowly, but was significantly higher than that in the LPS or hyperoxia stimulation alone group 4 hrs after stimulation.

CONCLUSIONS

Both LPS and hyperoxia exposure induced NF-kappaB activation in the HELFs in vitro. Hyperoxia combined with LPS induced a more prolonged duration of NF-kappaB activation. This suggests that the individuals who were subjected to intrauterine inflammation and postnatal hyperoxia exposure are more vulnerable to lung injury.