ABSTRACT
BACKGROUND: Systemic hyperglycemia is clearly related to severity of periodontitis, meaning that periodontitis can be exacerbated by diabetes mellitus (DM). However, the biologic mechanisms responsible for this relationship remain unclear. Thus, in this study, the global gene expression in gingival tissue with periodontitis is profiled in Zucker diabetic fatty (ZDF) rats compared with Zucker normoglycemic littermates (Lean). METHODS: At age 8 weeks, ZDF and Lean rats received ligature placement around the maxillary right second molar. At 0, 14, 28, 42, and 56 days after ligature placement, the maxilla around the molar was analyzed using microcomputed tomography. Two and 7 days after ligature placement, total RNA in the gingival tissue was isolated, and gene expression analysis was conducted using a rat oligo array. To validate the microarray findings, the selected genes were analyzed using real-time quantitative polymerase chain reaction assays. RESULTS: There was a significant difference regarding the average amount of bone resorption between ZDF and Lean rats from days 14 to 56. On day 2, it was found that 113 genes were regulated (20 upregulated, 93 downregulated) in the presence of DM. Lipopolysaccharide binding protein (LBP) messenger RNA (mRNA) expression was significantly higher in gingival tissue with periodontitis from ZDF rats compared with that from Lean rats. On day 7, interleukin (IL)-10 and IL-24 mRNA levels were significantly lower, whereas IL-2 level was significantly elevated. CONCLUSION: The results of this study indicate that the role of DM in modulating bone breakdown related to periodontitis may involve an increased level of LBP and reduced levels of T-helper 2 cytokines.
Subject(s)
Alveolar Bone Loss/etiology , Diabetes Mellitus, Experimental/genetics , Gingiva/metabolism , Periodontitis/etiology , Acute-Phase Proteins/analysis , Animals , Blood Glucose/analysis , Carrier Proteins/analysis , Cytokines/analysis , Diabetes Mellitus, Experimental/blood , Disease Models, Animal , Gene Expression Profiling/methods , Gene Expression Regulation , Imaging, Three-Dimensional/methods , Insulin/blood , Interleukin-10/analysis , Interleukin-2/analysis , Lipopolysaccharides/analysis , Male , Membrane Glycoproteins/analysis , Oligonucleotide Array Sequence Analysis/methods , RNA/analysis , Rats , Rats, Zucker , Real-Time Polymerase Chain Reaction/methods , Time Factors , Triglycerides/blood , X-Ray Microtomography/methodsABSTRACT
This study analyzes the effect of interleukin-15 (IL-15) on osteoclast formation using a coculture of mouse osteoblasts and bone marrow cells (BMCs) stimulated with prostaglandin E2 (PGE2), which both have important role in rheumatoid arthritis (RA) and periodontal disease (PD). BMCs isolate lacking T (BM(T-)) or NK (BM(NK-)) cells, BMCs with no cells removed (BM(T+NK+)), purified NK cells, and purified T cells were each cocultured with osteoblasts in the presence or absence of PGE2 and/or IL-15. The number of both osteoclasts and osteoblasts was decreased by IL-15 in a dose-dependent manner in BM(T+NK+), BM(T-). However, the reductions were improved in BM(NK-). The expression of caspase3 in osteoblasts cocultured with NK cells was increased in a dose-dependent manner by IL-15. IL-15 stimulates apoptosis of osteoblasts via activation of NK cells. Since osteoblasts have an important role in bone formation, IL-15 may be an inflammatory bone destructive factor in RA and PD.
Subject(s)
Cell Differentiation/immunology , Dinoprostone/pharmacology , Interleukin-15/pharmacology , Osteoblasts/cytology , Osteoclasts/cytology , Animals , Apoptosis/immunology , Arthritis, Rheumatoid/immunology , Bone Development/immunology , Bone Marrow Cells/immunology , Bone and Bones/immunology , Caspase 3/biosynthesis , Cell Differentiation/drug effects , Cells, Cultured , Coculture Techniques , Killer Cells, Natural/immunology , Mice , Periodontal Diseases/immunology , T-Lymphocytes/immunologyABSTRACT
AIM: Periodontal disease is highly prevalent and severe in diabetic patients, and is considered one of the diabetic complications. To elucidate how periodontitis progresses in diabetes, we examined an animal model of periodontitis in diabetic rats. MATERIALS AND METHODS: Two weeks after the induction of diabetes by streptozotocin, surgical nylon thread was ligated around the cervical portion of the unilateral maxillary second molar to induce periodontitis. Periodontitis was evaluated 2 weeks after the ligation by gingival blood flow, mRNA expressions, Western blot analysis, histological examination and micro CT. RESULTS: Ligation-induced severe periodontitis in the diabetic rats, which was apparently shown by the increase of TNF-α and iNOS mRNA expressions and inflammatory cell infiltration in the gingiva and alveolar bone loss. The number of nitrotyrosine, a footprint of nitrosative stress, -positive cells was significantly higher in the periodontitis of the diabetic rats compared with that in the normal rats. Western blot analysis confirmed that the nitrotyrosine was increased in the periodontitis of the diabetic rats. CONCLUSIONS: This is the first study to confirm increased nitrosative stress due to periodontitis in diabetic rats. Nitrosative stress may play a crucial role in the exacerbation of periodontitis in diabetic patients.
