ABSTRACT
[ ABSTRACT] AIM:To investigate the role of chronic psychological stress on periodontitis and the effects of hy-perbaric oxygen ( HBO) on periodontitis with psychological stress in rats.METHODS:Male special pathogen-free Wistar rats (n=80) were randomly divided into 4 groups:(1)normal control group;(2)experimental periodontitis group:the pe-riodontitis model was induced by wrapping 3/0 silk ligature inoculated with Porphyromonas gingivalis around the left maxil-lary second molar of the rats; ( 3 ) psychological stress stimulation group; ( 4 ) periodontitis model with stress stimulation group.Psychological stress was removed at the 9th week after ligature, and 4 rats from each experimental group were ran-domly chosen for HBO treatment.The rats were sacrificed at the 2nd, 4th, 8th and 10th weeks after ligature.The levels of blood glucose, adrenocorticotropic hormone ( ACTH) , corticosterone and adrenaline were measured as the stress markers. The histological changes of periodontal tissues were observed under microscope with HE staining.RESULTS:The levels of blood glucose, ACTH, corticosterone and adrenaline in psychological stress stimulation group and periodontitis with stress group were significantly higher than those in control group and experimental periodontitis group at the 2nd and 4th weeks af-ter ligature (P<0.05).The levels of the stress markers were significantly lower than those in untreated groups in the 10th week after HBO (P<0.01).The sites of gingival attachment were normal in control group and psychological stress stimu-lation group.Periodontal pocket, and periodontal attachment loss ( AL) were observed in experimental periodontitis group. The tissue damage was much heavier in periodontitis model with stress stimulation group as the furcation of tooth was ex-posed and the tissue damage was observed on both sides of the adjacent teeth.No significant difference of AL between psy-chological stress stimulation group and normal control group during the experiment was observed.The AL in periodontal model with stress stimulating group was significantly higher than that in experimental periodontitis group at the 2nd, 4th and 8th weeks (P<0.01).The level of AL was attenuated at the 10th week after HBO (P<0.01).No difference of histologi-cal change in periodontal tissues was observed between control group and psychological stress stimulation group.Severer in-flammatory changes and alveolar bone destruction were observed in periodontitis with stress group than those in experimental periodontitis group.The levels of inflammation reduced at the 10th week after HBO.CONCLUSION:Stress stimulation is one of the inducing factors of periodontitis in rats, which aggravates periodontitis.HBO may represent a useful way in trea-ting psychological stress periodontitis.