The Establishment Of Experimental Periodontitis In Rats Model And Osteoblasts Transfected By Lentivirus Vector Of Rno-miR-23a

In a variety of chronic inflammation of the jaw bone, periodontal and periapicaltissues, there will be bone resorption leisions to form, of which the most serious one idperiodontal bone loss. Periodontitis is an infectious disease that affects thetooth-supporting tissues and exhibits a wide range of clinical, microbiological andimmunological manifestations. The disease is associated with and is probably caused by amultifaceted dynamic interaction of specific infectious agents, host immune responses,harmful environmental exposure and genetic susceptibility factors. The ideal goal ofperiodontal therapy is periodontal regeneration, namely "complete structure and functionalperiodontal regeneration".MicroRNAs(miRNAs) were found at first by lee in the nematode cells,which in turnis proved to exist widely in plant and animal bodies. MiRNAs are the class of noncodingregulatory RNAs, binding to complementary sequences in the3`untranslated region(UTR)of mRNAto block protein translation and or modulate mRNAstability, and playingan important role of a wide range of biological processes. MiRNAs involve in growth, development and process of immune defense, aging diseases,etc, considered as themissing link in previous studies. Lee, etc screened out the differentially expressedmiRNAs in periodontitis tissues compaired with normal tissues; Zhou found that miR-18a, could promote the periodontal ligament derived stem cells(PDLSCs) to differentiateinto bone cells, and miR-23a involved in regulating osteoblast differentiation. Liu et al.found that miRNAs could constantly regulate the biological characteristics of PDLSCs inthe inflammatory environment.Now the mechanism of inflammatory bone resorption is not completely understood,so what a role may miRNAs play? If miRNAs do function in bone remodeling in theinflammatory condition, how?Aim:1To observe the bone resorption in rats with ligature-induced periodontitis andthe natural turnover after removing the ligation.2to gain rat osteoblasts of the down-expression and up-expression of mir-23a,preparing for in vivo transplantation. cultivate the osteoblast derived from neonatal rats.Method:132adult SD rats were randomly divided into4groups (n=8).The rightmaxillary first molar was assigned to receive wire ligation in the sulcular position,whilethe contralateral tooth was unligated as the control. The molars in group Awere ligated for7days;in group B for21days; in group C were ligated for21-days, then the ligation wasremoved and the rats were fed for another7days;in group D were ligated for21-days,then the ligation was removed and the rats were fed for another21days. At the end of theexperiment, the animals wer sacrificed and the periodontal tissue of the teeth wereexamined by micro-CT, HE and tartrate resistant acid-phosphatase(TRAP).2The osteoblast-like cells were tested mineralization ability by ALP and Alizarin redstaining, and analized the proliferation rate though MTT; the Lentivirus construction workis completed by Shanghai JiKai chemical technology services company; the virus vectortransfection of osteoblasts was viewed by confocal microscope; the MOI values werecalculate.Results:1Inflammatory infiltration in the gingival tissue,osteoclasts lining on thealveolar bone, and decreased alveolar bone height were observed in group A and B. The decrease of bone mineral density (BMD) under the fucation of group B was significant(P<0.05). In group C and D, the inflammation degree were reduced, the number ofosteoclasts decreased, and the alveolar bone height increased when compared with thosein group B (P<0.05).2ALP and Alizarin red staining results show that the cells have mineralizationability and is confirmed as the osteoblast cells; Confocal images show the successfultransfection, and that the virus can stably and constantly express. The MOI value is20.Conclusion:1In the ligature-induced periodontitis of rats model, ligation canpromote the development of periodontitis, while removal of the ligation can prevent thedevelopment of periodontitis,and activate the self-repair of periodontal tissues.2We Successfully gained the osteoblast-like cells of rats transfected by the lentivirusvector of rno-mir-23a and the cells can express the lentivirus sustainably.