Effects of bromelain, melatonin, and thymoquinone on neutrophil extracellular trap formation and macrophage polarization in experimental periodontitis

Abstract

Periodontitis is a chronic inflammatory disease characterized by dysregulated immune responses leading to alveolar bone loss. Formation of neutrophil extracellular traps and macrophage polarization play critical roles in its pathogenesis, and natural agents with immunomodulatory properties are being investigated as potential adjunctive therapies. Objective  This study aimed to compare the effects of systemically administered melatonin, bromelain, and thymoquinone on serum neutrophil extracellular trap formation and macrophage polarization in experimental periodontitis. Methodology  Forty rats were assigned to five groups: control, experimental periodontitis, and experimental periodontitis treated with melatonin, bromelain, or thymoquinone. Periodontitis was induced by ligature placement for 14 days. After ligature removal, the treatment groups received daily oral doses of melatonin, bromelain, or thymoquinone for 14 consecutive days. Biochemical, histologic, histomorphometric, and immunohistochemical analyses were performed. Comparisons between groups were performed using one-way ANOVA. Neutrophil extracellular trap levels measured before and after treatment within the same group were analyzed using a paired t-test. Results  Thymoquinone treatment significantly reduced alveolar bone loss compared to the bromelain and melatonin groups (p=0.00). The highest value was observed in the Periodontitis group and the lowest in the Thymoquinone group for neutrophil extracellular trap levels, with intergroup comparisons showing no statistically significant differences (p=0.597). All immunohistochemical analyses showed significant differences in all treatment groups compared to both the control and periodontitis groups (p=0.000). CD68(+) macrophages were most abundant in the periodontitis group and least in the Melatonin group (p=0.00). CD80 expression was highest in the Melatonin group and lowest in the Thymoquinone group (p=0.000), while CD206 expression was highest in the Bromelain group and lowest in the Thymoquinone group (p=0.00). Conclusion  Thymoquinone exhibited comparatively more favorable patterns, and overall, all agents showed trends that may support their consideration as adjunctive approaches in periodontitis management.