The results revealed that, compared to other groups, the IL-6 mRNA level in periodontal tissues of periodontitis mice exposed to hypobaric hypoxia for 1 day (PHH 1-day group) was significantly upregulated, and then this increase was followed by a downregulation with prolonged exposure to hypobaric hypoxia (Figure 1B). The gene discussed is IL6; the disease is periodontitis.