Y. Maruo et al., Accelerated DNA fragmentation of the denture-bearing mucosal epithelium inan animal model of diabetes, J ORAL REH, 28(4), 2001, pp. 393-399
This Study examined the effect of masticatory pressure transmitted directly
to the hard palate mucosa on the final stage of terminal differentiation o
f keratinizing system of rats with and without streptozotocin-induced diabe
tes mellitus. In the nondiabetic rats with masticatory pressure, the number
of terminal-deoxynucleotidyl-transferase-mediated deoxyuridine-triphospate
-biotin nick end labelling (TUNEL) positive cells tended to increase about
twice as much as in the nondiabetic rats without pressure with and without
denture. A similar tendency of increase was observed in the diabetic rats w
ithout pressure. The synergy of the mechanical pressure and diabetic condit
ion for 2 weeks greatly accelerated the DNA fragmentation, showing 8-fold i
ncrease in TUNEL positive cells over the normal control, and caused exfolia
tion of the stratum corneum. A 4-week exposure of diabetics to the masticat
ory pressure induced laminar splitting in the midst of the spinosum. Some c
ells in the stratum granulosum exhibited a sign of DNA fragmentation when l
aminar splitting took place in the vital cell layer. Premature DNA fragment
ation may disturb the adhesion between spinosum cells and prevent the matur
ation of stratum corneum. Increase in Bax protein-like immunoreactivity in
these epithelial cells as revealed by immunocytochemistry may underlie the
premature DNA fragmentation in the oral masticatory epithelium under pressu
re in diabetic patients.