Can chronic nasal obstruction cause dysfunction of the paratubal muscles and otitis media? An experimental study in developing Wistar rats

OBJECTIVE: To quantitatively analyze modifications of the paratubal muscles in developing Wistar rats following nasal obstruction. MATERIAL AND METHODS: Twenty-four Wistar rats were used. Twelve were examined at 6, 8 and 12 weeks after birth and were considered normal controls. The nostrils of the remaining 12 rats were bilaterally obstructed by means of a synthetic resin 28 days after birth. The animals were sacrificed at either 2, 4 or 8 weeks after nostril occlusion. Serial sections were made in the dorsoventral plane and stained with hematoxylin-eosin. Four 5 x 5 microm2 areas, selected within the paratubal muscles, were histologically analyzed and the number of muscular fibers was counted manually. RESULTS: The number of tensor veli palatini muscle fibers progressively decreased in the obstructed rats compared with age-matched normal controls and in those that had been obstructed for 4 and 8 weeks these reductions were statistically significant. CONCLUSION: The correct development of the paratubal muscles seems to be linked to physiological nasal breathing and is negatively affected by oral breathing.