Journal of Dental Research, Vol 72, 1233-1236, Copyright © 1993 by International & American Associations for Dental Research Online Journals
Nucleolar organizer regions as markers of incipient cellular alterations in squamous epithelium
A. E. Schwint, E. Gomez, M. E. Itoiz and R. L. Cabrini
Department of Radiobiology, National Atomic Energy Commission, Buenos Aires, Argentina.
Transcriptionally active nucleolar organizer regions identified by silver
staining (AgNOR) vary in number with cellular activity and/or malignant
transformation and have been used as a diagnostic tool. A morphometric
study of AgNORs was performed in an experimental model of irradiated
squamous epithelium (Wistar rat sole skin) 4, 8, and 14 hours and 1, 2, 5,
and 7 days post-irradiation with 50 Gy of x-rays. A statistically
significant and progressive rise in AgNOR average volume of up to 238% and
reduction in AgNOR number/nucleus of up to 40% were detected as a function
of post-irradiation time. A statistically significant 46% increase in AgNOR
volume was detected as early as 8 h post-irradiation, when no histological
changes were observable in routine preparations. These results suggest that
AgNORs may be useful as a quantitative marker of incipient changes in
cellular activity and caution against the indiscriminate use of AgNORs in
the follow-up of lesions which may have been exposed to radiotherapy.
Furthermore, this study suggests the possibility of using AgNORs as a
sensitive biological dosimeter in cases of uncontrolled exposure to
radiation.
