Lipid pigment (lipofuscin) accumulation in rat tongue muscle with aging.

Lipid pigment (lipofuscin) was examined in perioral and tongue muscles of aging rats. While in perioral striated muscle the pigmented granules could not be found, a considerable accumulation with aging could be noted in the tongue muscle. Unlike the human tongue muscle, in which the pigmented granules were stored in clusters of different sizes at the nuclear poles of the muscle fibers, in rats, they were scattered randomly through the cytoplasm. The results of this study suggest that lipofuscin can be used as a marker for aging of the tongue muscle in the rat.