Disrupted intestinal structure in a rat model of intermittent hypoxia

Obstructive sleep apnea (OSA) is a chronic condition characterized by chronic intermittent hypoxia (IH) and subsequent reoxygenation (ROX). The gastrointestinal system, which is particularly sensitive to tissue hypoxia and reduced perfusion, is likely to be affected by OSA. A rat model of IH was used to analyze oxidative stress-associated genes and tight junction proteins by reverse transcription‑quantitative polymerase chain reaction. Subsequently, altered morphology of the duodenal mucosa and elevated Chiu scores were observed in the IH‑exposed rats. In addition, IH exposure resulted in upregulation of the nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, NADPH oxidase 2 and p22phox, in the small intestine, and upregulation of transcription factors, including hypoxia‑inducible factor-1, nuclear factor‑κB and activator protein-1. Furthermore, the mRNA expression levels of intestinal tight junction (TJ)-related proteins, claudin-1 and claudin-4, were decreased in the IH‑exposed group, as compared with in the control group. In conclusion, the present study demonstrated that OSA, which is characterized by IH and ROX, may lead to disruption of the duodenum. The mechanism underlying the effects of OSA on duodenal morphology may be associated with increased oxidative stress and activation of transcription factors, subsequently inducing intestinal TJ disruption and intestinal injury.