ABSTRACT
The importance of fluoride (F) in preventing dental caries by favorably interfering in the demineralization-remineralization processes is well-established, but its ability to inhibit matrix metalloproteinases (MMPs), which could also help to prevent dentin caries, has not been investigated. This study assessed the ability of F to inhibit salivary and purified human gelatinases MMPs-2 and -9. Saliva was collected from 10 healthy individuals. Pooled saliva was centrifuged, and supernatants were incubated for 1 hr at 37°C and subjected to zymography. Sodium fluoride (50-275 ppm F) was added to the incubation buffer. The reversibility of the inhibition of MMPs-2 and -9 by NaF was tested by the addition of NaF (250-5,000 ppm F) to the incubation buffer, after which an additional incubation was performed in the absence of F. F decreased the activities of pro- and active forms of salivary and purified human MMPs in a dose-response manner. Purified gelatinases were completely inhibited by 200 ppm F (IC50 = 100 and 75 ppm F for MMPs-2 and -9, respectively), and salivary MMP-9 by 275 ppm F (IC50 = 200 ppm F). Inhibition was partially reversible at 250-1,500 ppm F, but was irreversible at 5,000 ppm F. This is the first study to describe the ability of NaF to inhibit MMPs completely.
Subject(s)
Cariostatic Agents/pharmacology , Matrix Metalloproteinase 2/drug effects , Matrix Metalloproteinase 9/drug effects , Matrix Metalloproteinase Inhibitors/pharmacology , Sodium Fluoride/pharmacology , Adult , Cariostatic Agents/administration & dosage , Dose-Response Relationship, Drug , Electrophoresis, Polyacrylamide Gel , Enzyme Precursors/antagonists & inhibitors , Humans , Matrix Metalloproteinase Inhibitors/administration & dosage , Saliva/enzymology , Salivary Proteins and Peptides/antagonists & inhibitors , Sodium Fluoride/administration & dosage , Temperature , Time Factors , Young AdultABSTRACT
Metalloproteinases (MMPs) have been implicated with metabolism of collagen in physiological and pathological processes in human dentine. As bovine teeth have been used as a substitute for human teeth in laboratory analysis, this study evaluated the activity of MMP-2 and -9 in bovine versus human dentine. Bovine and human dentine fragments, from crowns and roots, were powderized. Protein extraction was performed by two protocols: a neutral extraction with guanidine-HCl/EDTA (pH 7.4) and an acidic extraction with citric acid (pH 2.3). Gelatinolytic activities of extracts were revealed by zymography. MMP-2 and -9 were detected in crown and root dentine from bovine and human teeth. Total activities of MMP-2 were 11.4 ± 2.2, 14.6 ± 2.0, 9.7 ± 1.2 and 12.4 ± 0.9 ng/ml for bovine root, human root, bovine crown and human crown dentine, respectively. Corresponding activities for MMP-9 were 14.9 ± 2.0, 15.3 ± 1.3, 15.4 ± 1.3 and 15.5 ± 1.3 ng/ml, respectively. Bovine dentine was found to be a reliable substrate for studies involving the activity of MMP-2 and -9.