Periodontitis and diabetes interrelationships in rats: biochemical and histopathological variables

BackgroundA two-way relationship between diabetes and periodontitis is now clinically established. Both conditions share common mechanisms of pathogenesis that are related to altered immune-inflammatory responses at local and/or systemic levels. The aim of this study is to investigate whether periodontitis is associated with the development and progression of diabetes and to evaluate the health impact of coexistence of both diseases.Material and methodsMale Sprague Dawley rats (10weeks old) were randomized into seven groups (n=12): Group 1) Control; Groups 2 and 6) Periodontitis induced at two or six weeks; Groups 3 and 5) Diabetes induced at two or six weeks; Groups 4 and 7) Periodontitis followed by diabetes, and diabetes followed by periodontitis at two or six weeks. For diabetes induction, animals received a one-time intravenous injection of streptozotocin (50mg/kg). Periodontitis was induced by Lipoppolysaccharide injection (20g/rat) through the palatal gingival and by placing a ligature of 0/0 braided silk around the cervix of the upper right second molar. Body weight, glycaemia as well as urine were collected weekly. Rats were sacrificed at the end of week 10, gingival tissue was removed, fixed in formaldehyde and processed for histopathological study.ResultsBody weight was significantly decreased (25%) following diabetes induction (p<0.01). 40% weight loss was observed when diabetes was induced first compared to 30% when periodontitis was first induced in the animals (p<0.01). Rats treated with streptozotocin showed a three-fold increase in diabetes compared to the control group (p<0.01). In rats where periodontitis was induced after diabetes, glucose levels increased significantly (450mg/dL) compared to glucose levels (410mg/dL) where periodontitis was induced first (p<0.01). Histopathological studies showed greater alveolar bone loss when both diabetes and periodontitis were present.ConclusionWhen periodontitis occurs after diabetes it aggravates the symptoms of the two pathologies. When diabetes is induced after periodontitis, no symptoms aggravation is observed for diabetes, although periodontitis gets worse.