Local RAS exists in rat gingival tissue and is capable of generating Ang II and other vasoactive peptides in vitro.

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The effect of chronic fluoride (F) exposure from the drinking water on parameters related to glucose homeostasis was investigated. Wistar rats were randomly distributed into 2 groups (diabetic [D] and nondiabetic [ND]; n = 54 each). In D, diabetes was induced with streptozotocin. Each group was further divided into 3 subgroups (0, 10, or 50 mgF/L in drinking water). After 22 days of treatment, plasma and liver samples were collected. No alterations in glycemia, insulinemia, K(ITT), and HOMA2-IR (homeostasis model assessment 2 of insulin resistance) were seen for ND. F-exposure of D rats led to significantly lower insulinemia, without alterations in glycemia (increased %S). Proteomic analysis detected 19, 39, and 16 proteins differentially expressed for the comparisons D0 vs. D10, D0 vs. D50, and D10 vs. D50, respectively. Gene Ontology with the most significant terms in the comparisons D0 vs. D10, D0 vs. D50, and D50 vs. D10 were organic acid metabolic process and carboxylic acid metabolic process, organic acid metabolic process, and cellular ketone metabolic process. Analysis of subnetworks revealed that proteins with fold changes interacted with GLUT4 in comparison D0 vs. D10. Among these proteins, ERj3p was present in D10. Upregulation of this protein in the presence of F might help to explain the higher %S found in these animals. These data suggest that fluoride might enhance glucose homeostasis in diabetes and identify specific biological mechanisms that merit future studies.

The interactions of tetracycline (TC), oxytetracycline (OTC) and chlortetracycline (CTC) with ovalbumin (OVA), the main allergen protein of egg white, were investigated by molecular spectroscopy and electrophoresis at three pH conditions (1.5, 4.6 and 7.4). Molecular and synchronous fluorescence, UV-vis spectroscopy, electrophoresis and H NMR were used to study the interaction process. Tetracyclines interact with ovalbumin fluorescence by a static quenching mechanism with non-fluorescent complex formation changing the native protein structure. The binding constant (K) ranged from 2.11×10 to 58.4×10Lmol, and corresponding thermodynamic parameters were measured at different temperatures and pH values. The binding process was spontaneous (ΔG<0), and the magnitude of the interaction increased in the following order: TC

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The role of fluoride (F) in oxidative stress is well reported, but its effects on the lipid metabolism has not been completely exploredBackgroundHere, we evaluated the relationship of diet and F-induced oxidative stress to lipid metabolism in the liver of rats eating normocaloric or hypercaloric diets for two time periods (20 or 60 days).MethodsSeventy-two 21-day-old Wistar rats were divided into 2 groups (n = 36) based on the type of diet they were eating; each of these groups was then further divided into another two groups (n = 18) based on the time periods of either 20 or 60 days, for a total of four groups. Each of these was divided into 3 subgroups (n = 6 animals/subgroup), dependent on the dose of F administered in the drinking water (0 mg/L(control), 15 mg/L or 50 mg/L). After the experimental period, blood samples and the liver were collected. Plasma samples were analyzed for HDL, cholesterol and triglycerides. Western blots were performed to probe for GRP78, Erp29, SOD2, Apo-E and SREBP in hepatic tissues.ResultsAs expected,the expression of target proteins involved in oxidative stress increased in the F-treated groups, especially in liver tissue obtained from animals eating a hypercaloric diet. Most changes in the lipid levels and pathological conditions were seen earlier in the time period, at day 20. The morphometric analyses showed a reduction in steatosis in groups on ahypercaloric diet and treated with 50 mg F/L compared to the control, while no changes were obtained in normocaloric-fed rats. Accordingly, plasma TG was reduced in the F-treated group. The reduced expression of Apo-E in a time- and diet-dependent pattern may account for the particular decrease in steatosis in hypercaloric-fed F-treated rats.ConclusionsThese results suggest that F changes liver lipid homeostasis, possibly because of the induction of oxidative stress, which seems to be higher in animals fed hypercaloric diets.