Abstract:ObjectiveTo study the histopathological changes of soft palate and uvula in patients with obstructive sleep apnea hypopnea syndrome (OSAHS).MethodsSpecimens from 52 patients with OSAHS and 9 nonOSAHS adult cadavers were acquired. The 52 cases with OSAHS were divided into three groups by body mass index (BMI). The related clinical indexes in all groups were measured. Soft palate tissue sections were evaluated with light microscope (LM) and transmission electron microscope (TEM). Fat constituent ratio in all sections was measured by quantitative morphometric image analysis technique.Results①The BMI, neck circumference, waist circumference, waisttohip circumference ratio (WHR) of the obese OSAHS group were significantly higher than those of the other groups. ②LM and TEM studies showed similar pathological changes in three subgroups with OSAHS. The LM showed excessive fatty infiltration, partial atrophy and/or hypertrophy, and disordered arrangement of muscle fibers. The TEM showed focal or spotted deformity of Z line, sarcomere loss and vacuolation. Lipid droplet infiltration was also detected in adjoining myofibril. ③A significant difference in fat constituent ratio in soft palate was observed between the OSHAS group and the control group, while the differences among obese, overweight and normal weight subgroups of OSAHS were insignificant. ④The degree of fatty infiltration in soft palate tissue was positively correlated with WHR and AHI in the three subgroups of OSAHS.ConclusionExcessive fatty infiltration of oropharyngeal tissues and pathological changes of musculi pharyngopalatinus might exist in subjects with OSAHS. Abundant oropharyneal fatty infiltration might play an important role in pathogenesis of OSAHS via changing the size and shape of pharyngeal airway and therefore changing the compliance of pharyngeal wall.