A diet rich in omega-3 fatty acid improves periodontitis and tissue destruction by MMP2- and MMP9-linked inflammation in a murine model

Periodontitis is an oral-cavity inflammatory disease and is the principal cause associated with tooth loss. Matrix metalloproteinases 2 and 9 (MMP-2 and MMP-9) are important proteases involved in periodontal tissue destruction. The omega-3 polyunsaturated fatty acids (ω-3 PUFA) have been demonstrated to possess immunoregulatory properties in periodontitis. The aim of the study was to investigate the effects of ω-3 PUFA on inflammation and on the expression of MMP-2 and -9 in a murine periodontitis model. Twenty-four male C57BL/6 mice were divided into control mice (Control), control mice treated with ω-3 PUFA (O3), mice with periodontitis (P), and mice with periodontitis treated with ω-3 PUFA (P + O3). ω-3 PUFA were administered orally once a day for 70 days. Periodontitis in mice was induced by Porphyromonas gingivalis-infected ligature placement around the second maxillary molar. The mice were sacrificed, and blood and maxillary samples were collected. Flow cytometry was used to quantify tumor necrosis factor-alpha (TNFα), interleukin (IL)-2, IL-4, IL-5, and interferon-gamma. Histologic analysis and immunohistochemistry for MMP-2 and -9 were performed. The data were statistically evaluated using analysis of variance (ANOVA) and the Tukey post hoc test. Histological analysis showed that ω-3 PUFA supplementation prevented inflammation and tissue destruction and revealed that bone destruction was more extensive in the P group than in the P + O3 group (p < 0.05). Also, it decreased the serum expressions of TNFα and IL-2 and the tissue expression of MMP-2 and -9 in the periodontitis-induced model (p < 0.05). ω-3 PUFA supplementation prevented alveolar bone loss and periodontal destruction, probably by decreasing the expression of MMP-2 and MMP-9 and its immunoregulatory properties.

Aerobic training improves bone fragility by reducing the inflammatory microenvironment in bone tissue in type 2 diabetes

Aerobic training (AT) is indicated in type 2 diabetes mellitus (T2DM) to control hyperglycaemia and inflammation. AT improves bone microarchitecture and resistance to fracture. The intensity of AT and the mechanisms that lead to the improvement in bone quality are still unknown. Using a mouse model of T2DM, we evaluated the effects of two intensities of forced AT. We divided mice into: sedentary (SED), T2DM-SED, low runners (LOW), T2DM-LOW, high runners (HIGH) and T2DM-HIGH. The AT for low was 8 m/minute (m/min); 5° slope or high 18 m/min; 15° slope for 2 months. We measured metabolic parameters, the serum cytokines concentration, lipocalin-2 (LCN-2) and adiponectin; and the tibial concentrations of LCN-2, tumour necrosis factor alpha (TNF-α) and protein carbonylation (CO). We evaluated femur morphometry and biomechanical properties. We performed multiple correlation analysis. The T2DM-LOW versus T2DM-SED group, shown an increase of interleukin (IL)-10 (417 ± 90 vs 102 ± 25 pg/mL) and improved trabecular bone (BV/TV: 31.8 ± 2.3 vs 19.25 ± 1.4%; Tb.Sp.: 1.62 ± 0.02 vs 2.0 ± 0.07 mm), by a decrease bone CO (3.4 ± 0.1 vs 6.0 ± 0.5 nmol/mg), bone TNF-α (84 ± 4 vs 239 ± 13 pg/mL) and LCN-2 (2887 ± 23 vs 3418 ± 105 pg/mL). The T2DM-HIGH versus T2DM-SED group showed a greater hypoglycaemic effect (228 ± 10 vs 408 ± 5 mg/dL), with improved cortical bone density (0.26 ± 0.012 vs 0.21 ± 0.007 mm) and fracture resistance (102 ± 8 vs 78 ± 5 MPa), by a reduction of bone TNF-α (77 ± 34 vs 239 ± 13 pg/mL); LCN-2 (2768 ± 20 vs 3418 ± 105 pg/mL) and CO (4.8 ± 0.5 vs 6.0 ± 0.5 nmol/mg). In conclusion, AT improves bone morphometry and biomechanical properties by reducing the bone inflammatory microenvironment.