Measurement of peripheral vestibular blood flow in a gerbil model of endolymphatic hydrops.

Presently, many investigators believe that the dysfunction of microcirculatory mechanisms may be responsible for vestibular symptoms in Meniere's disease. This study, using intravital microscopy (IVM), a technique that provides in vivo microcirculatory measures, was designed to determine whether impaired vestibular blood flow exists in endolymphatic hydrops. Hydrops was induced in the gerbil model by obliteration of the vestibular aqueduct and was confirmed histologically after IVM. Posthydrops gerbil subjects at 8 weeks as well as control animals were prepared for IVM. With a customized intravital microscope, red blood cell velocity and vessel diameter measurements were calculated for individual arterioles and capillaries from the microvascular bed at the horizontal ampulla. Mean arteriole diameter was significantly larger in the control group than in the hydrops group, whereas mean capillary diameters were similar for both groups. No significant difference was observed for mean red blood cell velocity in capillaries or arterioles between control and hydrops animals.