J Sleep Res. 2020;00:e13065. wileyonlinelibrary.com/journal/jsr | 1 of 7 https://doi.org/10.1111/jsr.13065 © 2020 European Sleep Research Society 1 | INTRODUCTION Sleep deprivation, which is a type of sleep disorder, generates oxida- tive stress in an organism and has acute and chronic adverse effects on well-being by causing biochemical changes. Although the acute manifestations mainly include disturbed neuromediator homeosta- sis in the central nervous system, changes in hormonal regulation and alterations in sympathetic and parasympathetic system activity, eating disorders, psychosocial disorders, thermoregulation disor- ders and a disturbed blood lipid profile occur in the chronic period and can result in morbidity and mortality (Pilcher & Huffcutt 1999). Disorders of connective tissue elements and impairments in the regulation of connective tissue mediators associated with sleep dep- rivation may lead to prolonged wound healing and deterioration of immunity, and induce negative regulation systems in ageing physiol- ogy (Opp & Toth 2003). Received: 7 January 2020 | Revised: 28 March 2020 | Accepted: 20 April 2020 DOI: 10.1111/jsr.13065 REGULAR RESEARCH PAPER Effects of chronic sleep deprivation on upper respiratory tract mucosal histology and mucociliary clearance on rats Fatma Cemre Sazak Kundi | Kursat Murat Ozcan | Berna Okudan | Nazim Coskun | Mehmet Arda Inan | Muge Ozcan Department of Otorhinolaryngology, Ankara Numune Training and Research Hospital, Ankara, Turkey Correspondence Fatma Cemre Sazak Kundi, Department of Otorhinolaryngology, Ankara Numune Training and Research Hospital, Sihhiye, Altindag 06600, Ankara, Turkey. Email: fatmacemresazak@hotmail.com Abstract In this study, we aimed to investigate the effects of chronic sleep deprivation on mucociliary clearance, which is the primary defence mechanism of the upper airway tract and nasal mucosal histology. Forty-two Wistar Albino rats (250-300 g), 8 or 12 weeks old, were randomly assigned into three groups as follows. The first sleep- deprivation group consisted of 14 rats (A), another 14 of them were assigned to plat- form group (B), and the remaining 14 were included to the home cage control group (C). For the two deprivation groups (A and B), the modified multiple platform method (MMPM) was used to induce sleep deprivation for 21 days. Tc-99m MAA rhinoscin- tigraphy was performed to assess mucociliary clearance and the nasal histopatho- logical changes of the sacrificed rats were also examined. Mucociliary clearance was significantly higher in sleep deprivation (A) and deprivation control (B) groups than the control group (C) ( p = .037). The ratio of columnar ciliary was significantly higher in group A and B than in the control group ( p = .003). The transitional epithelial ratio in groups A and B was also significantly increased compared with group C ( p = .04). The control group's squamous epithelial ratio was increased compared to the sleep- deprived groups ( p = .003). There was a significantly increased inflammatory re- sponse in the ciliated columnar epithelium in groups A and B compared to group C ( p = .02). For the first time in the literature, we demonstrated that chronic sleep deprivation has caused a significant increase in mucociliary clearance speed and in the number of ciliary cells. KEYWORDS rapid eye movement deprivation, mucociliary clearance, sleep deprivation