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Epithelial Thickness and Labelling Index in Young and Old Mice 1
Author(s) -
Ettinger Ronald L.,
Mackenzie Ian C.
Publication year - 1986
Publication title -
gerodontology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.7
H-Index - 54
eISSN - 1741-2358
pISSN - 0734-0664
DOI - 10.1111/j.1741-2358.1986.tb00066.x
Subject(s) - stratum corneum , medicine , epithelium , epidermis (zoology) , tongue , pathology , anatomy , hard palate , dentistry
The Labelling Index (L.I.), thickness and number of cell layers in the stratum corneum of various epithelia of groups of eight‐week‐old and two‐year‐old mice were compared. Arbitrarily selected subgroups of 5 animals were injected with 1μ Ci/gm body weight of 3 H‐TdR at 6 hourly intervals. Two hours after injection, specimens of skin from ear and footpad and of mucosa from tongue and palate were removed and either prepared for autoradiography or frozen for cryotomy and histological assessment. Most tissues showed a significant diurnal variation in L.I. In the older animals the L.I. was lower in all tissues except the palate (no change) and ear epidermis (higher). The thickness of the epithelium of the old animals was less in the palate but greater in the ear and footpad. The number of cell layers of the stratum corneum, when visualized by alkaline expansion, was unchanged in the footpad but significantly increased in the ears of the old mice.