Abstract :
Micronuclei (MN) are fragments of
chromosomes that fail to encompass into the
nucleus and remains in the cytoplasm in cell
division course (1). Monitoring MN in oral
exfoliated epithelial cells for detecting exposed
individuals to genotoxic agents was proposed by
Stich et al. in 1982 for the first time (2).
The genotoxic agents of tobacco, waterpipe and
even environmental contaminants are recognized
as initiator factors in producing the aberrations that
results in MN production (3-5). Assessing the
frequency of MN in oral exfoliated cells is a noninvasive reliable indicator of genotoxic damage in
human (6).
Among different staining methods to
demonstrate the nuclear abnormalities, Feulgen is
one of the most reliable method. The Feulgen
staining is a specific and sensitive method for
evaluating DNA damages. It has been shown that
using non-DNA specific stains to monitor nuclear
anomalies lead to false-positive or false-negative
results (7).
In a routine Feulgen staining technique, slides
are immersed in 5 mol/L HCl for 15 minutes,
rinsed with distilled water for 3 minutes, stained
with Schiff's reagent for 90 minutes, washed for 10
minutes and finally stained with 1% light green for
15 minutes (7-8). Using the Feulgen staining,
nucleus and micronuclei appear magenta and
cytoplasm seems green.
