Excessive fluoride intake alters the MMP-2, TIMP-1 and TGF-beta levels of periodontal soft tissues: an experimental study in rabbits

Abstract

Objectives This study evaluated the influence of fluoride on periodontal soft tissues by investigating any alterations in their MMP-2, TIMP-1 and TGF-beta profiles secondary to excessive fluoride intake. Material and methods Fluorosis was induced in 18 rabbits (test group) through consumption of fluoride added to drinking water, whereas 10 rabbits consumed regular tap water as daily supply (control group). Following fluorosis verification, animals were sacrificed and their 1st mandibular molar teeth were utilized in the assessments. MMP-2, TIMP-1 and TGF-beta were separately investigated for gingival epithelium (GE), gingival connective tissue (GC) and periodontal ligament (PL) to evaluate periodontal soft tissues. Histological sections were prepared from the groups, the parameters were determined by immunohistochemistry, and their levels were calculated by quantification of the immunostainings. Results Staining intensity of MMP-2 in GC and PL (p < 0.01); TIMP-1 and TGF-beta of GE, GC and PL (p < 0.01) were higher in the test group compared to those of the control group. Intra-group staining of TIMP-1 was higher than MMP-2 in all test group compartments (p < 0.01) and in the control group GE (p < 0.01). TIMP-1 was also higher than TGF-beta in the GE and PL of the test group (p < 0.05) and in the GE of the control group (p < 0.01). Conclusion These results suggest that excessive fluoride intake may affect periodontal soft tissues by increasing MMP-2, TIMP-1 and TGF-beta, and thereby altering the MMP-2/TIMP-1 and TIMP-1/TGF-beta ratios. Clinical relevance Excessive fluoride consumption may alter the periodontal tissue homeostasis which may be detrimental in the maintenance of periodontal health.