Impact of chronic simulated snoring on carotid atherosclerosis in rabbits

Abstract

Background and purpose: Chronic simulated snoring was induced in rabbits to determine the impact of snoring on the development of atherosclerosis.

Methods: The pressure wave of induced snoring at the carotid bifurcation of rabbits was acquired by gently pressing the airway. This wave was then simulated using custom-made mechanical devices. Twelve rabbits were used in this study, seven of which were assigned to the experimental group and the remaining five formed the control group. All of the rabbits were raised on a 1% high-cholesterol diet. Either working or sham devices were positioned at the ventral center of the neck in each rabbit. At the end of a 2-month observation period, all of the rabbits were sacrificed by perfusion fixation, the carotid arteries harvested, and the carotid atherosclerosis histology reviewed.

Results: All of the rabbits survived to the end of the experimental period. Blood sampling revealed the presence of hypercholesterolemia in both groups, with no significant difference between them. The presence and degree of atherosclerosis did not differ significantly between the groups.

Conclusions: The findings of this study show the feasibility of making a chronic simulated snoring rabbit model. However, the causative role of snoring in carotid atherosclerosis was not detected in this animal study.

Keywords: atherosclerosis; carotid artery; hypercholesterolemia; induced snoring; rabbit.

Fig. 1

Modeling of snoring. A: Baseline. B: Induced snoring by placement of a sandbag on the airway. C: Simulated snoring by intermittent motor activation. High-frequency waves caused by snoring are marked by arrows (B) and arrowheads (C). Horizontal bar=500 ms; vertical bar=1.5 mm Hg.

Fig. 2

A rabbit wearing a custom-made vest for long-term vibration simulation. A: The custom-made vest. B: Motor with a rotor, controller-mounted circuit board, and a battery pack. C: The fully equipped rabbit.

Fig. 3

Histologic findings of the harvested carotid arteries. A: Right carotid artery of rabbit #12 (control group) showing no definite atherosclerotic change. B: Right carotid artery of rabbit 35 (experimental group) showing focal infiltration of foamy cells under the intima (arrow). C: Right carotid artery of rabbit #8 (control group) showing multiple layers of foamy cell infiltration (arrow) with focal denudation of the intima (arrowhead). Hematoxylin-eosin stain. Scale bar=500 µm.