Role of PGC-1 alpha in fiber type conversion in the palatopharyngeus muscle of OSA patients

Background: Obstructive sleep apnea (OSA) has a high incidence and is harmful to health. It is characterized by repeated collapse of the upper airway. However, the mechanism underlying upper airway collapse is unclear. Methods: Patients with OSA and chronic tonsillitis were studied. Pathological changes in palatopharyngeus muscle were detected. The expression of peroxisome proliferator-activated receptor-gamma co-activator-1 alpha (PGC-1 alpha) and nuclear respiratory factor-1 (NRF-1) in muscles was detected by PCR and Western blotting. Immunofluorescence staining was used to detect the expression of type I and type II myofibril. Results: The structure of the palatopharyngeus muscle was changed, and the expression of PGC-1 alpha and NRF-1 was decreased in the OSA group compared with that in the control group. The expression of PGC-1 alpha, NRF-1, and type I myofibril in C2C12 myoblasts was decreased by intermittent hypoxia exposure. The expression of type I myofibril was decreased when knocking down PGC-1 alpha. Conclusion: OSA patients exhibited pathological damage in palatopharyngeus muscle. PGC-1 alpha was involved in the fiber type conversion in palatopharyngeus muscle caused by intermittent hypoxia.