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

Presently, many investigators believe that the dysfunction of microcirculat ory mechanisms may be responsible for vestibular symptoms in Meniere's dise ase. This study, using intravital microscopy (IVM), a technique that provid es in vivo microcirculatory measures, was designed to determine whether imp aired vestibular blood flow exists in endolymphatic hydrops. Hydrops was in duced in the gerbil model by obliteration of the vestibular aqueduct and wa s confirmed histologically after IVM. Posthydrops gerbil subjects at 8 week s as well as control animals were prepared for IVM. With a customized intra vital microscope, red blood cell velocity and vessel diameter measurements were calculated for individual arterioles and capillaries from the microvas cular bed at the horizontal ampulla. Mean arteriole diameter was significan tly larger in the control group than in the hydrops group, whereas mean cap illary diameters were similar for both groups. No significant difference wa s observed for mean red blood cell velocity in capillaries or arterioles be tween control and hydrops animals.