Inner ear pathology of alpha-galactosidase A deficient mice, a model of Fabry disease.

Abstract

OBJECTIVE: Fabry disease is characterized by genetic alpha-galactosidase A deficiency, resulting in accumulation of glycolipids (GL-3) and tissue damage. Hearing loss is also common and attributed to GL-3 accumulation in the inner ear. The only reported histological studies dealt with murine and human specimens. Accordingly, histopathological studies of the cochlea were performed on an alpha-galactosidase A deficient murine model of Fabry disease, using C57BL6/J mice as the controls. METHODS: The hearing ability was evaluated using the ABR threshold, while cochlear specimens were observed light microscopically and ultrathin temporal bone sections by TEM. RESULTS: HE staining showed no accumulation of GL-3 or abnormal cochlear morphology in the alpha-galactosidase A deficient mice, but toluidine blue staining and TEM revealed GL-3 accumulation in the stria vascularis and kidney. No GL-3 accumulation was detected in the C57BL6/J controls by either HE staining or TEM. The alpha-galactosidase A deficient mice and the controls showed no clear differences in the ABR threshold (hearing acuity), but for older animals the threshold was higher in the C57BL6/J controls. CONCLUSION: In summary, although the alpha-galactosidase A deficient mice showed no clear hearing loss, GL-3 accumulation was demonstrated in the cochlea.