Vestibular morphology in the German Waltzing guinea pig.
OBJECTIVE
The German waltzing guinea pig is a special strain of animal with a recessively inherited inner ear defect, resulting in deafness and a severe vestibular dysfunction. The hearing loss in the cochlea of the German strain is a result of a collapse of the Reissner membrane and the absence of scala media. The vestibular organ has not yet been described.


METHODS
German waltzing guinea pigs (homozygote and heterozygote) of different ages ranging from embryologic age 25 days to adulthood were investigated. The living animals were tested with four different vestibular tests, and the fetuses were controlled according to breeding. The morphology of the vestibular parts (ampulla, saccule, and utricle) was observed by using the light and transmission electron microscopy.


RESULTS
Collapse of the membranous labyrinth was found already at embryologic age 50 days and progressed over time. Vestibular dysfunction was noted already from birth.


CONCLUSIONS
Vestibular atelectasis has been shown to have the same morphology as the reported vestibular dysfunction in the German waltzing guinea pig. Owing to this similarity, this animal can be a good model for vestibular research.
Kawaguchi
Sachie
S
Center for Hearing and Communication Research, Karolinska Institute, Stockholm, Sweden. schk7578@tokyo-med.ac.jp
Hultcrantz
Malou
M
Jin
Zhe
Z
Ulfendahl
Mats
M
Suzuki
Mamoru
M
D000818:Animals; D004195:Disease Models, Animal; D006168:Guinea Pigs / Q000033:anatomy & histology*; D010641:Phenotype; D014722:Vestibule, Labyrinth / Q000648:ultrastructure*