Investigation of the Effects of Calendula officinalis on Gingival Tissue in Streptozotocin-Induced Diabetic Rats

Objective: This study aimed to evaluate the effects of Calendula officinalis administration on inflammatory changes in gingival tissue in a streptozotocin-induced experimental diabetes model.Methods: Twenty-eight male Sprague-Dawley rats were randomly divided into four groups (n=7): control (C), Calendula officinalis (CO), diabetes mellitus (DM), and diabetes mellitus + Calendula officinalis (DM+CO).Diabetes was induced by intraperitoneal administration of streptozotocin (50 mg/kg), and Calendula officinalis extract was administered by oral gavage at 250 mg/kg for six weeks.Gingival cyclooxygenase-2 (COX-2) and interleukin-1β (IL-1β) levels were determined by ELISA and normalized to total protein concentrations.Gingival tissues were also evaluated histopathologically using hematoxylin and eosin and Masson's trichrome staining.Results: Gingival COX-2 and IL-1β levels were significantly higher in the DM group than in the control group (p=0.011 and p=0.017, respectively).In the DM+CO group, both COX-2 and IL-1β levels were significantly lower than those in the DM group (p=0.026 for both).Histopathological evaluation revealed epithelial and connective tissue irregularities in the DM group.In the DM+CO group, the epithelial-connective tissue junction appeared more regular and distinct, and connective tissue organization exhibited a more regular morphological appearance than in the DM group.Conclusion: Calendula officinalis administration was associated with lower gingival COX-2 and IL-1β levels in STZ-induced diabetic rats.The accompanying histopathological observations suggest that its antiinflammatory effects may also be reflected in gingival tissue morphology.Further studies incorporating quantitative histomorphometric analyses and broader inflammatory and oxidative stress markers are warranted.