Effect of a sugarcane cystatin on the profile and viability of microcosm biofilm and on dentin demineralization.

To analyze the effect of a sugarcane cystatin (CaneCPI-5) on the microbial profile and viability, as well as on the prevention of dentin demineralization using a microcosm biofilm model. Ninety bovine dentine specimens were divided into five experimental groups according with the solution they were treated for 60 s: (1) PBS (negative control), (2) 0.12% chlorhexidine (positive control), (3) Fluoride (500 ppm F, as NaF), (4) 0.025 mg/ml CaneCPI-5, and (5) 0.05 mg/ml CaneCPI-5. Specimens were incubated with inoculum (McBain's saliva plus human saliva) in the first 8 h, and from then on, they were exposed to McBain saliva containing sucrose and daily treated (60 s) with the solutions for 5 days. Resazurin and colony-forming unit counting assays were performed. Dentin demineralization was measured by transverse micro-radiography (TMR). 0.12% chlorhexidine significantly reduced the metabolic activity of the microcosm biofilm in relation to the negative control and treated groups (p < 0.01). CHX and F significantly reduced the counts of total microorganisms, mutans group streptococci, and lactobacilli when compared with the negative control. None of the treatments was able to significantly reduce dentin demineralization in comparison with the negative control. In the model evaluated, CaneCPI-5 neither altered the microcosm biofilm profile and viability nor protected dentin against demineralization.

Changes in energy metabolism induced by fluoride: Insights from inside the mitochondria.

The mechanisms involved in changes in energy metabolism caused by excessive exposure to fluoride (F) are not completely understood. The present study employed proteomic tools to investigate the molecular mechanisms underlying the dose- and time-dependency of the effects of F in the rat liver mitochondria. Thirty-six male Wistar rats received water containing 0, 15 or 50 mgF/L (as NaF) for 20 or 60 days. Rat liver mitochondria were isolated and the proteome profiles were examined using label-free quantitative nLC-MS/MS. PLGS software was used to detect changes in protein expression among the different groups. The bioinformatics analysis was done using the software CYTOSCAPE® 3.0.7 (Java®) with the aid of ClueGo plugin. The dose of 15 mgF/L, when administered for 20 days, reduced glycolysis, which was counterbalanced by an increase in other energetic pathways. At 60 days, however, an increase in all energy pathways was observed. On the other hand, the dose of 50 mgF/L, when administered for 20 days, reduced the enzymes involved in all energetic pathways, indicating a lower rate of energy production, with less generation of ROS and consequent reduction of antioxidant enzymes. However, when the 50 mgF/L dose was administered for 60 days, an increase in energy metabolism was seen but in general no changes were observed in the antioxidant enzymes. Except for the group treated with 50 mgF/L for 20 days, all the other groups had alterations in proteins in attempt to maintain calcium homeostasis and avoid apoptosis. The results suggest that the organism seems to adapt to the effects of F over time, activating pathways to reduce the toxicity of this ion. Ultimately, our findings corroborate the safety of the use of fluoride for caries control.