Abstract:

[Abstract]   Objective   To measure the mRNA expression of immediate-early gene c-fos in endothelial cells by the
use of different intermittent hypoxia (IH) protocols.  Methods   A gas control delivery system was homemade, which produced IH/ re-oxygenation(ROX) environmental exposure. The endothelial cells were exposed to IH/ROX cycles, and were divided into three groups (A, B and C). There were five sub-groups in each group. Group A included intermittent normoxia group, standard incubator control group, continuous hypoxia group (CH),1.5%O2 IH group and10%O2 IH group. There were different frequency IH of1.5%O2 and10%O2sub-groups in group B and group C. Hypoxia time was15s. The intermittent hypoxia cycle was60and the ROX time was different. The total cycle time was different, including1.5h group,3h group,5h group,6.5h group and9.5h group. The mRNA expression of immediate-early gene c-fos was measured by real-time PCR.  Results   There was no significant difference in the level of c-fos mRNA between intermittent normoxia group and CH group. The expression of c-fos mRNA was significantly higher in1.5%O2 IH group and10%O2 IH group than that of intermittent normoxia group, and there was a higher expression level of c-fos mRNA in 1.5%O2 IH group than that of 10%O2 IHgroup (P<0.01). It was found that the mRNA expression of c-fos increased gradually at first, and then gradually decreased. The expression of c-fos mRNA was significantly higher in5h group than that of other groups (P<0.01).   Conclusion   The mRNA expression of immediate-early gene c-fos is increased after exposing to IH/ROX in endothelial cells, which isclosely related with IH extents and frequencies.

Key words: Key wordsleep apnea, obstructive, anoxia, genes, fos, oxidative stress, endothelial cells