Biochemical and histopathologic analysis of the effects of periodontitis on left ventricular heart tissues of rats.

BACKGROUND AND OBJECTIVE: Current epidemiological works have suggested that chronic infections, such as periodontitis, are associated with an increased risk of cardiovascular diseases, including hypertrophy and heart failure. However, mechanisms behind the association are not known. The aim of this study was to evaluate the effects of periodontitis on the serum lipid levels, inflammatory marker levels and left ventricular heart muscle tissues of rats. MATERIAL AND METHODS: Eighteen male Sprague-Dawley rats were randomly divided into two groups: control (without ligature) and experimental periodontitis (EP; ligatured). Periodontitis was induced by placing ligatures (3.0 silk) at a submarginal position of the lower first molar teeth for 5 wk. Serum samples were collected for biochemical studies (C-reactive protein, interleukin-1ß, tumor necrosis factor-α and serum lipids), after which the rats were killed and heart tissue samples were obtained for histopathological and immunological studies (nuclear factor kappa B and ß-myosin heavy chain). RESULTS: Significant increases in C-reactive protein and interleukin-1ß levels and no statistically significant increase in tumor necrosis factor-α level were observed in the EP group compared to the control group. In addition, total cholesterol, low-density lipoprotein cholesterol and triglyceride levels were significantly higher in the EP group. Stereological and immunological findings showed that the number of nuclear factor kappa B-p65- and ß-myosin heavy chain-positive cardiomyocytes increased significantly in the left ventricular tissue samples of the rats with periodontitis. CONCLUSION: Early chronic phase effects of periodontitis on heart tissue are in the form of degenerative and hypotrophic changes. Prolonging the exposure to systemic inflammatory stress may increase the risk of occurrence of hypertrophic changes.

Melatonin prevents radiation-induced oxidative stress and periodontal tissue breakdown in irradiated rats with experimental periodontitis.

BACKGROUND AND OBJECTIVE: The aim of this study was to analyze the biochemical and histochemical effects of radiation therapy and protective melatonin administration on periodontal tissues in rats with experimental periodontitis. MATERIAL AND METHODS: Sixty male Sprague Dawley rats were divided into six groups, as follows: control; experimental periodontitis (Ped); radiotherapy administration (Rt); experimental periodontitis and exposure to irradiation (Ped-Rt); radiotherapy and protective melatonin administration (Rt-Mel); and periodontitis, radiation therapy and protective melatonin administration (Ped-Rt-Mel). The rats were killed at the end of the experimental procedure, and the oxidative stress level and periodontal destruction were compared among the groups. RESULTS: The oxidative stress index and the levels of 8-hydroxy-2'-deoxyguanosine, malondialdehyde and C-terminal telopeptide of type I collagen were found to be significantly higher in the Ped-Rt group compared with the Ped group (p < 0.05), and the levels were lower in the Ped-Rt-Mel group than in the Ped-Rt group (p < 0.05). Alveolar bone destruction and attachment level were also significantly lower in the Ped-Rt-Mel group than in the Ped-Rt group (p < 0.05). CONCLUSION: It was found that radiotherapy increased oxidative stress, the periodontal attachment level and alveolar bone loss, and protective melatonin administration significantly reduced the oxidative parameters and prevented periodontal damage in irradiated rats with experimental periodontitis. Further research is needed regarding the use of systemic melatonin administration before radiation therapy.