Chronic intermittent hypoxia disturbs insulin secretion and causes pancreatic injury via the MAPK signaling pathway

Obstructive sleep apnea (OSA) is a breathing disorder during sleep, with a most prominent character of chronic intermittent hypoxia (CIH), which induces the generation of reactive oxygen species (ROS) that damages multiple tissues and causes metabolic disorders. In this study, we established a rat model of varying OSA with different grades of CIH (12.5% O-2, 10% O-2, 7.5% O-2, and 5% O-2) for 12 weeks, and found that CIH stimulated insulin secretion, reduced the insulin: proinsulin ratio in pancreatic tissue, and caused pancreatic tissue lesions and cell apoptosis in a dose-dependent manner. Moreover, CIH promoted the production of tumor necrosis factor (TNF)-alpha, interleukin (IL)-1 beta and IL-6, and activated mitogen-activated protein kinase (MAPK) family members, extracellular regulated protein kinase (ERK), c-Jun N-terminal kinase (JNK), and P38, depending on the O2 concentration. In summary, CIH disturbed insulin secretion, and caused inflammation, lesions, and cell apoptosis in pancreatic tissue via the MAPK signaling pathway, which may be of great significance for clinical treatment of OSA and type 2 diabetes mellitus (T2DM).