Does Sex Matter in Obesity-Induced Periodontal Inflammation in the SS^LepR Mutant Rats?

Introduction: The incidence of obesity has dramatically increased worldwide. Obesity has been shown to exacerbate the progression of periodontal disease. Studies suggest a sex difference in periodontitis, whereby males are more sensitive to periodontal inflammation compared to females. Aim: In the current study, it was hypothesized that obesity drives periodontal inflammation and bone loss in both sexes. Methodology: Utilizing leptin receptor mutant (SS^LepR mutant) rats as a genetic model of obesity, 11-12-week-old male and female lean Dahl salt-sensitive (SS) rats and obese SS^LepR mutant rats were used to investigate sex differences in obesity-induced periodontal inflammation. Results: Body weight, insulin, hemoglobin A1c and cholesterol levels were significantly elevated in the obese SS^LepR mutant strain vs. the lean SS strain within the same sex. Sex differences in body weight and plasma hemoglobin A1c were only observed in obese SS^LepR mutant rats, with males having significantly greater body weight and hemoglobin A1c vs. females. Plasma thiobarbituric acid reactive substances (TBARs) and monocyte chemoattractant protein-1 (MCP-1), markers of systemic oxidative stress and inflammation, respectively, were significantly elevated in obese SS^LepR mutant rats vs. lean SS rats, with no sex differences in these parameters in either rat strains. Although micro-CT analyses of the maxillary first molar alveolar bone from obese SS^LepR mutant rats revealed no evidence of bone loss and/or sex differences, immuno-histochemical analysis revealed significant elevations in periodontal IL-6 and decreases in IL-10 in obese SS^LepR mutant rats vs. lean SS rats, with no apparent sex differences in these parameters. Conclusions: Obesity increases systemic and periodontal inflammation, without evidence of bone loss or apparent sex differences in SS^LepR mutant rats.