Lipofuscin pigments in the spiral ganglion of the rat.

The purpose of the present study was to clarify morphological differences in lipofuscin or so-called age pigments observed in the spiral ganglion cells of both young and adult rat groups and to characterize the size and structure of ceroid pigment granules generated in vitamin-E-deficient rats. The results showed different patterns of lipofuscin distribution in the two groups. The adult rat group had large aggregated lipoid, dark pigment granules of irregular shape in the cytoplasm. In contrast, the young group had small numbers of small, dense homogeneous granules, suggesting higher Schwann cell phagocytic activity. The ceroid pigments apparently included numerous vesicles and droplets of more variable density and size than the lipofuscin pigments appearing in the non-treated older animals. Both lipofuscin and ceroid pigments developing in such non-dividing cells are produced as a result of peroxidation reactions, so that the more they accumulate in the cytoplasm the more likely cell function deteriorates. The present study has shown that lipofuscin/ceroid granules are generated in the spiral ganglions under either endogenous (aging) or exogenous (vitamin E deficiency) conditions.