| Periodontitis is a chronic non-specific infectious disease,mainly due to the invasion of periodontal tissue by plaque biofilm,which induces immune responses to the host's immune response.As the disease progresses,the soft and hard tissues are destroyed,and early manifestations are Periodontal soft tissue inflammation and alveolar bone resorption,late tooth loosening occurred.It is reported that the prevalence of periodontitis in adults in the United States reaches 47%.In China,the prevalence of adult periodontitis is as high as 80%,Obviously,periodontitis has become a common and frequently-occurring disease that threatens human health.Therefore,it is of great significance to study the alveolar bone resorption mechanism caused by inflammation,inhibit inflammatory alveolar bone resorption,strengthen bone remodeling,and promote bone regeneration for human oral health and even whole-body health.In recent years,the regulation of osteoblasts and osteoclasts by microRNAs has become a research hotspot.microRNA-34a(microRNA-3 4a,miR-34a)not only plays a regulatory role in cell proliferation,cycle,apoptosis and other physiological or pathological processes.In bone remodeling,a number of experimental results at home and abroad show that miR-34 a can be Inhibition of LPS-induced macrophage inflammatory response,inhibition of osteoclast formation and reduce bone resorption,in addition,miR-34 a can promote osteogenic differentiation of human bone marrow mesenchymal stem cells and adipose stem cells.miR-34 a can promote the osteogenic differentiation of many types of stem cells,but it is limited by its own negative charge,hydrophilicity and susceptibility to degradation.In this experiment,N-Ac-L-Leu-modifi-ed PEI derivative(N-Ac-L-Leu-PEI)was used as a novel delivery medium for miR-34 a to establish a highly targeted and biocompatible N-Ac-L-Leu-PEI/miR-34 a nanocomplexes to investigate the role of miR-34 a loaded on N-Ac-L-Leu-PEI in the osteogenic differentiation of rat bone marrow mesenchymal stem cells(BMSCs).The future gene therapy for alveolar bone resorption lays a certain experimental basis Methods:The different mass ratios of N-Ac-L-Leu-PEI/miR-34 a complexes were incubated with BMSCs,the transfection efficiency of BMSCs was detected by flow cytometry,the proliferation of BMSCs was detected by MTT assay,screening out the optimal transfection quality ratio of N-Ac-L-Leu-PEI/mi R-34 a complexes in BMSCs;BMSCs were stimulated by the optimal mass ratio of N-Ac-L-Leu-PEI/miR-34 a complexes,the Cells? alkaline phosphatase activities were detected by alkaline phosphatase kit,the Cells? osteogenic marker gene expression of RUNX2,SP7 and Col ? were detected by real-time quantitative polymerase chain reaction.Results:The transfection efficiency of N-Ac-L-Leu-PEI/mi R-34 a complex with mass ratio of 4: 1 in BMSCs was higher than that in other groups,the impact of BMSCs proliferation was weaker than that of other groups,at the same time,this mass ratio complex can promote alkaline phosphatase release from BMSCs.Although the effect of the complex on osteogenic marker gene expression was not consistent with that of the blank control group,however,the N-Ac-L-Leu-PEI/miR-34 a complex with the mass ratio of 4: 1 promoted mRNA expression of RUNX2,SP7 and Col? in comparison with the N-Ac-L-Leu-PEI group.Conclusions:1.Under the condition of relatively weak influence on the proliferation of BMSCs,the optimal transfection ratio of N-Ac-L-Leu-PEI and miR-34 a is 4:1.2.N-Ac-L-Leu-PEI can be used as an effective carrier of miR-34 a to assist miR-34 a to promote osteogenic differentiation of BMSCs. |
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