The effect of diabetes mellitus on the expression of Argyrophilic nucleolar organizer regions (AgNORs) in mucosal epithelium under experimental denture bases in rats

Background: Expression of argyrophilic nucleolar organizer regions (AgNOR) was counted on mucosal epithelium to detect whether the AgNOR count (the number of AgNOR per nucleus) is, for 20 weeks, affected by streptozotocin-induced diabetes mellitus. Methods: Diabetic rats were applied non-denture wearing, nonpressure contact, continuous pressure (0.5, 1.5 or 3.4 kPa) and intermittent pressure (10.5, 33.0 or 81.7 kPa), respectively. Results: In the non-denture wearing or the non-pressure contact group, AgNOR count was almost constant (ranging 1.86-1.92) without significant difference. Under continuous pressure, AgNOR count significantly decreased at earlier stage and finally recovered to the non-pressure contact group. A similar effect of continuous pressure appeared to manifest itself in intermittent pressure, but to a greater degree. Consequently, AgNOR count under intermittent pressure showed no recovery at 20-week stage. Conclusion: Diabetes mellitus exerted, by itself, no influence on the cellular proliferative activity under continuous pressure, whereas the activity deteriorated under intermittent pressure.