NOS2 and obstructive sleep apnea syndrome: BM-MSCs (5 × 106 cells), which were intravenously infused 24 h after OSA induction and every 4 days for three weeks, prevented collagen deposition, normalized vascular remodeling and completely reversed aortic structural changes by attenuating superoxide anion production, by suppressing ACE-1 activity and by increasing iNOS expression in the aortas of OS rats [35].