Effects Of Quercetin On The Treatment Of Periodontium And Lung Tissue In Rats With Experimental Passive Smoking Periodontitis

Objective: The rat model of experimental periodontitis was established by periodontal ligation and the experimental passive smoking model was established by closed fumigation.The local treatment model of periodontitis was established by removing the ligament.The quit smoking model was established by stopping fumigation at the same time with quercetin drug treatment.The morphology of the periodontal tissue of rat,the morphology of the lung tissue of rat and the expression of protein tyrosine phosphatase-2(SHP-2)in periodontal tissues were observed.In order to investigate the effects of passive smoking on the inflammation of periodontal tissue and lung tissue in rats,the therapeutic effect of quercetin on periodontitis and lung injury,the theoretical basis and experimental reference for the clinical application of quercetin in the treatment of periodontitis and tobacco-induced lung injury caused by passive smoking were needed.Methods: Eighty-eight 6-month-old male SD rats were used.10 rats were randomly selected as normal group(N group).Then the remaining rats were randomly divided into three groups: periodontitis group(L group),passive smoking group(P group),periodontitis + passive smoking group(LP group).L&LP group were treated with periodontal ligament,P&LP group were treated by closed fumigation.After 8 weeks,all the rats in the N group were killed,and 6 rats were randomly selected in the L&P&LP group were killed respectively.Then the maxilla and lung tissues were taken.At the same time,the ligations of remaining rats in L&LP group were removed under anesthesia.The closed fumigation of remaining rats in P&LP group were stopped.Then the remaining rats in the L&P&LP group were randomly divided into two groups: Periodontal therapy + Quercetin group(RL+Q group),Periodontal therapy + Blank group(RL+S group),Quiting smoking + Quercetin group(SP+Q group),Quiting smoking + Blank group(SP+S group),Periodontal therapy + Quiting smoking + quercetin group(RL+SP+Q group),Periodontal therapy + Quiting smoking + Blank group(RL+SP+S group),quercetin by 80mg/(kg·d)administration,normal feeding.After 8 weeks,rats in each group were killed,and the specimens of maxilla and lung were taken,then fixed in 10% formalin solution for 48 hours and the maxillary specimens were decalcified in 10% EDTA solution.The morphological changes of periodontal and lung tissue were observed by HE stainings.The expression of SHP-2 in periodontal tissues was detected by immunohistochemistry.The results were analyzed statistically.Results: 1 Normal group(N group): After 8 weeks with regular food feeding,the periodontal tissues were observed: the color and morphology of gingiva were well;A small amount of soft dirt on the surface of the teeth;Gingival sulcus located at the cement enamel junction boundaries.Under optical microscope: Few inflammatory cells infiltration were found in epithelial connective tissues.The shape of alveolar crest was regular.2 After 8 weeks of periodontal ligament and closed fumigation,the results of periodontal tissues: 2.1 Periodontitis group(L group): The naked eye observation: Obvious redness and swelling of the gingiva;A lot of soft dirt around the ligament;Bleeding on probing periodontal tissue;Periodontal pocket was formed.Under optical microscope: The attachment level of junctional epithelium moved to the root.All the rats showed osteoclasts and lacunas in alveolar bone,the top of alveolar crest bone was absorbed and alveolar bone proper was destroyed.Immunohistochemical stainings showed: The expression of SHP-2 in the periodontal tissues in L group compared with the N group was increased.There was a significant difference(P<0.05).2.2 Passive smoking group(P group): The naked eye observation: Redness and swelling of the gingiva;Bleeding on probing;Gingival sulcus located at the cement enamel junction boundaries.Under optical microscope: A small amount of inflammatory cells infiltration were found in epithelial connective tissues.The shape of alveolar crest was irregular.Immunoh-istochemical stainings showed: The expression of SHP-2 in periodontal tissues in P group compared with the N group was increased.There was a significant difference(P<0.05).2.3 Periodontitis + Passive smoking group(LP group): The naked eye observation: Obvious redness and swelling of the gingiva;A lot of soft dirt around the ligament;Bleeding on probing;Periodontal pocket was formed.Under optical microscope: the attachment of junctional epithelium moved to the root.All the rats showed a large number of osteoclasts and lacunas in alveolar bone.The top of alveolar crest bone was absorbed and alveolar bone proper was destroyed seriously.Immunohistochemical stainings showed: The expression of SHP-2 in periodontal tissues in LP group compared with the L group was increased.There was a significant difference(P<0.05).3 Normal group(N group): After 8 weeks with regular food feeding,the lung tissues were observed: the color was pink and bright,and the flexibility was well;Under optical microscope: Few inflammatory cells were found in interstitial lung and pulmonary bronchial wall.The alveolar septum and bronchial mucosal cilias were regular.4 After 8 weeks of periodontal ligament and closed fumigation,the results of lung tissues: 4.1 Periodontitis group(L group): The naked eye observation: The color and morphology of lung were similar to normal.Under optical microscope: Few inflammatory cells were found in interstitial lung and pulmonary bronchial wall;The telangiectasia and congestion were found in alveolar septum occasionally.The bronchial mucosal cilias was regular.4.2 Passive smoking group(P group): The naked eye observation: The color of lung was pale and the some part was brownish black.The flexibility of lung tissues was poor.Under optical microscope: A number of inflammatory cells were found in interstitial lung and pulmonary bronchial wall;The telangiectasia and congestion were found in alveolar septum.The bronchial mucosal cilias were decreased or disappeared.4.3 Periodontitis + Passive smoking group(LP group): The naked eye observation: The color of lung was pale and the some part was brownish black.The flexibility of lung tissues was poor.Under optical microscope: A large number of inflammatory cells were found in interstitial lung and pulmonary bronchial wall;The telangiectasia and congestion were found in alveolar septum seriously.The bronchial mucosal cilias were decreased or disappeared.5 To remove the ligament and stop the closed fumigation at the same time with quercetin drug treatment.After 8 weeks,the results of periodontal tissues: 5.1 Periodontal therapy + Quercetin group(RL+Q group): The naked eye observation: gingival papilla slightly inflamed;The depth of periodontal pockets were decreased.Under optical microscope: A small amount of inflammatory cells infiltration were found in epithelial connective tissues.A large number of new fibrous connective tissue were found between periodontal pocket and alveolar bone.A number of osteoblasts were found in alveolar bone resorption.Immunohistochemical stainings showed: The expression of SHP-2 in periodontal tissues in RL+Q group compared with the RL+S group was decreased obviously.There was a significant difference(P<0.05).5.2 Quiting smoking + Quercetin group(SP+Q group): The naked eye observation: Gingival color and morphology were similar to normal where the gingival sulcus located at the cement enamel junction boundaries.Under optical microscope: Few inflammatory cells infiltration were found in epithelial connective tissues.The shape of alveolar crest was close to normal.Immunohistochemical stainings showed: The expression of SHP-2 in periodontal tissues in SP+Q group compared with the SP+S was decreased obviously.There was a significant difference(P<0.05).5.3 Periodontal therapy + Quiting smoking + Quercetin group(RL+SP+ Q group): The naked eye observation: Gingival papilla was slightly inflamed.The depth of periodontal pockets were decreased.Under optical microscope: A small amount of inflammatory cells infiltration were found in epithelial connective tissues.A large number of new fibrous connective tissues were found between periodontal pocket and alveolar bone.More osteoblasts were found in alveolar bone resorption site.Immunohistochemical stainings showed: The expression of SHP-2 in periodontal tissues in RL+SP+Q group compared with the RL+SP+S group was decreased obviously.There was a significant difference(P<0.05).5.4 Periodontal therapy + Blank group(RL+S group),Quiting smoking + Blank group(SP+S group),and Periodontal treatment + Quiting smoking + Blank group(RL+SP+S group): There were no significant improvements in periodontal tissues.Immunohistochemical stainings showed: RL+S group compared with L group,SP+S group compared with P group,RL+SP+S group compared with LP group: The expression of SHP-2 in periodontal tissues has no significant difference(P>0.05).6 To remove the ligament and stop fumigation at the same time with quercetin drug treatment.After 8 weeks,the results of lung tissues: 6.1 Periodontal therapy + Quercetin group(RL+Q group): the naked eye observation: The color and morphology of lung were similar to normal.Under optical microscope: Few inflammatory cells were found in interstitial lung and pulmonary bronchial wall;The telangiectasia and congestion were not found in alveolar septum.The bronchial mucosal cilias were regular.6.2 Quiting smoking + Quercetin group(SP+Q group): The naked eye observation: The color of lung was bright and the flexibility looked better.Under optical microscope: A small amount of inflammatory cells were found in interstitial lung and pulmonary bronchial wall;The telangiectasia and congestion were found in alveolar septum occasionally.6.3 Periodontal therapy + Quiting smoking + Quercetin group(RL+SP+Q group): The naked eye observation: The color of lung was bright and the flexibility looked better.Under optical microscope: A small amount of inflammatory cells were found in interstitial lung and pulmonary bronchial wall;The telangiectasia and congestion were found in alveolar septum occasionally.6.4 Quiting smoking + Blank group(SP+S group),Periodontal treatment + Blank group(RL+S group)and Periodontal treatment + Stopping passive smoking + Blank group(RL+SP+S group): There has no significant improvement in lung tissues.Conclusions:1 The experimental periodontitis animal model was successfully established by orthodontic ligation with maxillary first molar combined with high glucose food feeding of rats.2 The experimental passive smoking model was successfully established by closed fumigation of rats.3 Passive smoking can cause and aggravate inflammatory changes in periodontal tissue.4 Passive smoking can cause lung injury.5 Quercetin has a therapeutic effect on periodontitis and lung injury caused by passive smoking.