Expression Of Inflammatory Factors In Rat Model Of Hyperlipidemia With Periodontitis

Objective:1.Firstly,a rat model of hyperlipidemia was established by specific high-fat diet,and then periodontitis model was established by periodontal ligation.The relationship between hyperlipidemia and periodontitis was further studied.2.The gingival tissues of rats in each group were extracted and the expression of cathepsin K(CTSK),adiponectin(APN),receptor activator for nuclear factor-kB ligand(RANKL)at gene and protein levels were detected.The role of cathepsin K(CTSK),adiponectin(APN),and receptor activator for nuclear factor-kB ligand(RANKL)in the pathogenesis and their relationship were preliminarily explored.Methods:Forty male SD rats were randomly divided into four groups:A-normal,B-periodontitis,C-hyperlipidemia,D-hyperlipidemia+ periodontitis,with 10 rats in each group.1.Four groups of rats were fed in cages.Group A and B were fed with common diet,and group C and D were fed with high-fat diet for 14 weeks.At 6 weeks,blood samples were collected from four groups of rats to analyze whether hyperlipidemia model was established.Then the periodontitis model wasestablished by ligation of the left first maxillary molar for 8 weeks in group B and D.At 14 weeks,serum lipids and alkaline phosphatase(ALP)were measured,periodontal depth(PD)and gingival sulcus bleeding index(SBI)were examined,and maxilla were taken for HE staining and micro-CT scanning.2.The expression of CTSK,APN and RANKL at gene and protein levels were observed by RT-PCR and Western blot.3.Statistical analysis: SPSS19.0 statistical software was used to test the normality of the data,which was expressed by mean(+standard deviation).Variance analysis or rank sum test were used for comparison among groups of data,and SNK method was used for comparison between groups of data.The detection level was bilateral a=0.05.P<0.05 showed significant difference.Results: 1 Establish an animal model of hyperlipidemia with periodontitis.1.1 Serological tests showed that:(1)at the 6th week of high-fat diet,total cholesterol(TC),triglyceride(TG),low-density lipoprotein(LDL-C)increased,high-density lipoprotein(HDL-C)decreased,with statistical significance;(2)at the 14 th week,serum ALP activity in group B and C was higher than that in group A and group B,and group D was higher than that in group B,with statistical significance.Meaning(P<0.05).1.2 Periodontal clinical examination:(1)After 8 weeks of periodontal ligation,the PD value of group B was higher than that of group A,group D was higher than that of group B,and group D was higher than that of group C,with statistical difference(P<0.05).(2)After 8 weeks of periodontal ligation,the SBI value of group B was higher than that of group A,and that of group D was higher than that of group C(P<0.05).1.3 Histopathology showed that the periodontal tissues in group A were basically normal;periodontal ligament fibers in group B were destroyed and the epithelial roots migrated;a small amount of inflammatory cells infiltrated in connective tissue in group C;and dense inflammatory cells infiltrated in group D,osteoclasts could be seen.1.4 The alveolar bone loss in group B was higher than that in group A,and the alveolar bone loss in group D was more serious than that in group B and C(P<0.05).2 The expression of CTSK,RANKL and APN in gingival tissue:The gene and protein levels of CTSK and RANKL showed that group B and C were larger than group A,with statistical significance(P<0.05).Group D was larger than group B and C,with statistical difference(P<0.05).APN gene and protein levels showed that group B and C were smaller than group A,with statistical significance(P<0.05).Group B was larger than group D,with statistical difference(P<0.05).Conclusions:1.SD male rats were fed with specific high-fat diet for 6 weeks to establish hyperlipidemia model,and experimental periodontitis model was established after 8 weeks of periodontal ligation.2.Micro-CT showed that alveolar bone resorption in hyperlipidemia rats with periodontitis was more serious than that in simple periodontitis rats.It suggests that hyperlipidemia can promote the development of periodontitis.3.The expressions of CTSK and RANKL in hyperlipidemia rats with periodontitis were higher than those in simple periodontitis rats.It suggests that hyperlipidemia increases the expression of pro-inflammatory factors.The expression of APN in rats with hyperlipidemia and periodontitis was lower than that in rats with simple periodontitis,suggesting that APN as an anti-inflammatory factor decreased the expression of periodontitis further.