Effect of Quercetin on filiform and fungiform papillae of the tongue of albino rats with induced diabetes

Objective: The aim of the present work was to study the effect of Quercetin on the structure of filiform and fungiform papillae of the tongue in albino rats with streptozotocin induced diabetes.
Design: Thirty adult male Wistar rats were divided into 3 equal groups (10 rats each): Group 1 (control group), Group 2: (diabetic group) and Group 3: (Quercetin treated diabetic group). In both groups 2&3 diabetes was induced by single intraperitoneal injection of streptozotocin (50 mg/kg). After confirmation of diabetes, Quercetin was administrated to group 3 (50 mg/kg/day) orally for 12 weeks. Then all rats were sacrificed and the tongues were dissected out for light microscopic (LM) examination, immunohistochemical examination, histomorphometric analysis and scanning electron microscopic (SEM) examination.
Results: LM examination of diabetic group revealed disturbances in filiform papillae with hyperkeratosis. Fungiform papillae exhibited slight elongation with separation between taste bud cells. SEM examination revealed disturbance in the normal orientation of filiform papillae which appeared thin. On the other hand, in Quercetin treated group, there was marked improvement in the shape and orientation of the papillae. However, some changes were observed by LM which included hyperkeratosis and in SEM some filiform papillae appeared thin. Immunohistochemical analysis revealed strong reaction for caspase 3 in diabetic group, while in Quercetin treated group the reaction was mild. Quercetin treatment resulted in significant decrease in both area percentage of immunopositive cells and the optical density of caspase 3 immunostaining which was significantly increased after induction of diabetes.
Conclusions: In a rat model, Quercetin can to a great extent overcome most of the detrimental effects of diabetes on the structure of both filiform and fungiform papillae of the tongue.