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 anti-inflammatory effects may also be reflected in gingival tissue morphology. Further studies incorporating quantitative histomorphometric analyses and broader inflammatory and oxidative stress markers are warranted.