An animal model of a spontaneously reversible obstructive sleep apnea syndrome in the monkey

The anatomies of the tongue and uvula in monkeys share many similarities with humans, such that this species has the closest approximation to the human upper airway than any other species. In this study, we investigated the feasibility of using small monkeys as experimental animals for an obstructive sleep apnea model. Monkeys received intradermal injections of liquid collagen in the uvula, tongue, and lateral pharyngeal walls every 2 weeks. Polysomnography was performed bi-monthly in order to control the impact of injections on breathing events, respiratory effort (as measured by esophageal pressure), and sleep. Before injections, the three animals showed normal breathing during sleep with a mean of 4.8 +/- 2.0 events/h. After injections, a mean of 27.9 +/- 19.7 hypopneas/h was recorded (P = 0.023). Total sleep time was significantly reduced, with a decrease of REM sleep and stage II sleep; however, stage I sleep increased. Collagen injections in monkey's upper airways can create sleep-disordered breathing and abnormal sleep, as seen in sleep apneic patients.