FIGURE 1.

(a) Representative view of the experimental IH protocol. The concentration of oxygen was alternated from 21%–5% in the IH groups. The dashed line represents the setting point used for adjusting O₂ levels in the chamber. (b) Experimental design of the study design. All animals were habituated three days before to the chamber apparatus and IH protocol (gray square). The animals were subjected to IH or normoxia (control) daily (8 AM–4 PM) for 1, 2, 3, 4, or 5 weeks. Control and IH groups are time‐matched and were euthanized in the same day (B)