The Effects Of Different Interventions Of CKIP-1 SiRNA On The Progression Of Periodontitis-an Experimental Periodontal Animal Model Study

Background Periodontitis is an inflammatory and destructive disease involving the periodontal support tissues including the gums,periodontal ligament,cementum and alveolar bone.Particularly,alveolar bone resorption is a major pathological change of periodontitis.Due to the absorption of alveolar bone,the height of the supporting tissue of the tooth is reduced,and the tooth is gradually loosened and eventually detached or removed.At present,the treatment of periodontitis is mainly to control inflammation in the clinical.However,the absorption of alveolar bone is difficult to return to normal.how to promote the absorption of alveolar bone to recover or how to delay the degree of the absorption of alveolar bone is the key issue of clinical treatment.Casein kinase 2-interacting protein 1(CKIP-1)is a negative regulatory of bone formation.CKIP-1 can negatively regulate the differentiation and activation of osteoblast and accelerate the degradation of the osteoblast and substrate by accelerating the E3 activity of Smurf l,promoting the degradation of Smad1 and Smad5 protein and inhibiting the signal transduction of BMP pathway.CKIP-1 plays an important role in bone development,bone remodeling and bone regeneration.Osteoblasts are the major functional cells for bone formation,and they are differentiated by bone marrow mesenchymal stem cells(BMSCs).Therefore,how to improve BMSCs proliferation and osteogenic differentiation is become a new idea of treatment of periodontitis.It has been found that CKIP-1 can affect the bone formation of mice by inhibiting the proliferation and osteogenic differentiation of BMSCs at the cellular level,and the loss of CKIP-1 can significantly improve the BMSCs' ability to repair bone defects.There are many studies of CKIP-1 knockout animal models on osteoporosis.RNA interference(RNAi)is a highly specific method of gene silencing that is used for in vivo gene at the translational stage.Based on the negative regulation of CKIP-1 on osteogenic differentiation of BMSCs,CKIP-1 si RN A can silence target genes to promote the osteogenic differentiation of BMSCs.In this study,we will observe the CKIP-1 si RNA interference uesd in rat periodontal model to explore its impact on the progression of periodontitis.Objective 1.To observe the different methods for the establishment of rat periodontal model,to explore the success of rat modeling and its natural recovery time.2.To provide more theoretical and experimental evidences for the role and application of CKIP-1 in the treatment of periodontitis by observing the effects of CKIP-1 si RNA on the development of periodontal model in rats.Methods 1.Establishment of rat periodontitis model: The rat periodontal model was established by LPS-PG injection,4-0 thin-line ligation and LPS-PG injection combined with 4-0 thin-line ligation.Micro-CT imaging is used to observe the differences of the bone resorption in periodontal models.2.Determination of recovery time in periodontal model: The rat periodontal model was established by LPS-PG injection combined with 4-0 thin-line ligation.After 1,2,3 and 4 weeks,respectively,the recovery of periodontitis was observed in periodontal model without any intervention.Micro-CT imaging is used to observe and compare the volume at the bifurcation and the height of alveolar bone.3.Effects of CKIP-1 si RNA Interference in the rat periodontal model: During and after the establishment of rat periodontal model,we conduct the intervention experiments by injecting saline,NC si RNA and CKIP-1 si RNA respectively.The volume at the bifurcation and the height of alveolar bone are observed by micro-CT and HE staining to analyse statistically the effects of periodontal progression in rats.Results 1.Rat periodontal model results showed that LPS-PG injection combined with 4-0 thin line ligation group and LPS-PG injection group have obvious periodontal pocket formarion at the third week of the experiment,bleeding on probing positive;while the 4-0 thin line ligation group did not show such results until the fourth week of the experiment.Micro-CT imaging results showed that the LPS-PG injection combined with 4-0 thin line ligation group and the LPS-PG injection group have obvious resorption of alveolar bone at the third week of the experiment,but most of bone resorption lacated at the injection sites with angular character;4-0 thin line ligation group did not have obvious bone resorption at the fourth week of the experiment.2.Four weeks after the LPS-PG injection combined with 4-0 thin-ligation group,all the interventions were removed.The results of micro-CT imaging showed that the remodeling of alveolar bone was obvious after three weeks of recovery,and the volume at the bifurcation and the height of alveolar bone are basically as same as that of the normal SD rats after four weeks of recovery.3.The results of micro-CT imaging showed that the alveolar bone defects in NS group and NC si RN A group were more obvious than that of CKIP-1 si RN A group during the modeling,and the alveolar bone remodeling in CKIP-1 si RNA group was more obvious than that of NS group and NC si RN A group after the modeling.In the intervention experiment during the modeling,the results of histological observation showed that the alveolar bone was absorbed more obviously and the periodontal fiber sort was more disordered in NS group and NC si RNA group.Compared with NS group and NC si RN A group,remodeling of alveolar bone was more obvious in CKIP-1 si RNA group after modeling.Conclusion 1.With the LPS-PG injection combined with 4-0 thin-ligation method,significant and stable bone resorption can be rapidly established within 4 weeks.2.The established models can be recovered in four weeks if let it free.3.Silencing the CKIP-1 gene by si RN A interference can improve bone remodeling and reduce bone resorption in rat periodontal model.