Osteogenesis Of Loaded SiRNA Collagen/Bioglass Composites

Objective Restoration of lost alveolar bone is always a hot topic in medical research.On the one hand,it was found that siRNA(small interfering RNA)was able to induce sequence specific gene silencing in the late 1990.With the discovery of the role of RNAi(RNA interference),siRNA was widely used to promote osteogenesis.On the other hand,the bone material emerges in an endless stream.Because of excellent osteogenic activity of bioactive glass and excellent biological properties of collagen,collagen/bioactive glass composites is highly-anticipated.Based on these experimental results,this project intends to combine the effects of siRNA and collagen/bioactive glass on osteogenesis,design Collagen/bioactive glass scaffolds loaded with siRNA,and realize that the bidirectional synchronization of collagen/bioactive glass material and siRNA promote the local osteogenesis synchronously.Methods We used PEI(polyethyleneimine)to encapsulate siRNA,and then select the siRNA that can specifically and effectively suppresses noggin expression by q-PCR.The loaded siRNA collagen/bioglass composites were prepared by freeze-drying method.The scaffold material characterization,mechanical properties,swelling rate,degradation rate and siRNA release rate were evaluated.Micro CT and confocal microscopy were used to observe the adhesion and growth of MC3T3-E1 in scaffolds.The CCK8 kit was carried to detect the proliferation at selected time point.On day 14,the ALP activity assay,q-PCR and Alizarin Red Solution were conducted to detect the effect of scaffold on mineralization.Resulst One of three customized noggin siRNA could effectively inhibit the expression of noggin.The loaded siRNA collagen/bioglass composites as sponge-like material.Scanning electron microscopy showed that the bioactive glass is evenly dispersed in the collagen material.Compressive strength is low and porosity is appropriate.After the first week,the swelling rate was 12.9%,the degradation rate was 30.7%,and the siRNA was released with the degradation of the material.Cells form pseudopods on the material,tightly adhere to the surface of the material.And the cells are tightly connected.The number of cells proliferated in the loaded collagen/bioglass group was significantly higher than that in the blank group(P <0.05),the difference was statistically significant.PCR detect that the interference efficiency of siRNA release from the material is 16%(P <0.05),the difference was statistically significant.After co-culture for 14 days,the expression of ALP,Runx2 and BSP gene in siRNA collagen/bioglass scaffold group was higher than that in pure scaffold group,the difference was statistically significant.And RAS results showed that the loaded siRNA collagen/bioglass group had more mineralized nodules than the rest(P <0.05),the difference was statistically significant.Conclusions The loaded si RNA collagen/bioglass composite prepared by freeze-drying method,si RNA noggin maintains activity in the composites.The composites has good biocompatibility and furthermore collagen/bioglass composite and si RNA noggin can promote the osteogenesis synchronously.