Study objectives: To determine whether the vibratory mechanical stimulus due to snoring induces upper-airway inflammation in an in-vivo rat model.
Design: Prospective controlled animal study.
Setting: University laboratory.
Patients or participants: Sixteen male Sprague-Dawley rats (250-300 g).
Interventions: The upper trachea of 8 rats was cannulated, and the upper airway was subjected to vibration (60 Hz; +/- 10 cm H2O) with a periodic pattern consisting of 1 second of vibration followed by 3 seconds of no vibration. This snoring-like vibration was applied for 3 hours. The animals breathed spontaneously through a cannula in the lower trachea. In a control group (8 rats), the animals were similarly instrumented, but no upper-airway vibration was applied.
Measurements and results: The effect of vibration was assessed by measuring the vibration-induced increase in gene expression of the pro-inflammatory cytokine tumor necrosis factor-alpha and of the neutrophil attractant chemokine macrophage inflammatory protein-2 in the soft-palate tissue. Real-time reverse-transcription polymerase chain reaction measurement of mRNA showed that vibration induced a significant overexpression of both tumor necrosis factor-alpha and macrophage inflammatory protein-2: 6.01-fold +/- 2.47-fold (p = .005) and 2.38-fold +/- 0.54 -fold (p = .021) increase when compared with control (mean +/- SEM).
Conclusions: The mechanical stimulus of vibration per se triggers an early proinflammatory process in the upper airway.