Construction of hollow polydopamine nanoparticle based drug sustainable release system and its application in bone regeneration / 国际口腔科学杂志·英文版

Nanomaterial-based drug sustainable release systems have been tentatively applied to bone regeneration. They, however, still face disadvantages of high toxicity, low biocompatibility, and low drug-load capacity. In view of the low toxicity and high biocompatibility of polymer nanomaterials and the excellent load capacity of hollow nanomaterials with high specific surface area, we evaluated the hollow polydopamine nanoparticles (HPDA NPs), in order to find an optimal system to effectively deliver the osteogenic drugs to improve treatment of bone defect. Data demonstrated that the HPDA NPs synthesized herein could efficiently load four types of osteogenic drugs and the drugs can effectively release from the HPDA NPs for a relatively longer time in vitro and in vivo with low toxicity and high biocompatibility. Results of qRT-PCR, ALP, and alizarin red S staining showed that drugs released from the HPDA NPs could promote osteogenic differentiation and proliferation of rat bone marrow mesenchymal stem cells (rBMSCs) in vitro. Image data from micro-CT and H&E staining showed that all four osteogenic drugs released from the HPDA NPs effectively promoted bone regeneration in the defect of tooth extraction fossa in vivo, especially tacrolimus. These results suggest that the HPDA NPs, the biodegradable hollow polymer nanoparticles with high drug load rate and sustainable release ability, have good prospect to treat the bone defect in future clinical practice.

Expressions of cell polarity related proteins CDC42and PAR3 during tooth germ development in mice / 吉林大学学报(医学版)

Objective:To study the expressions of cell polarity related proteins CDC42 and PAR3 during tooth germ development in the mice,and to discuss their possible roles during tooth development in the mice.Methods:The whole heads were obtained from the mouse embryo on the days 13.5,14.5,16.5 and 18.5 (E13.5,E14.5,E16.5 and E18.5) and the mice on the postnatal days 1 (PN1) and 5 (PN5).The tissues were fixed in paraformaldehyde,decalcified,dehydrated,embedded in paraffin,and sectioned.The histology of tooth germ was observed by HE staining.The expressions of CDC42 and PAR3 during tooth germ development were detected by immunohistochemistry staining.Results:The HE staining results showed that E13.5,E14.5,E16.5 and E18.5were the bud stage,the cap stage,the early and the late bell stage of tooth germ development,respectively;the tooth germ of PN1 mice showed the matured odontoblasts and ameloblasts;the tooth germ of PN5 mice showed the completed tooth crown development.The immunohistochemistry staining results showed that CDC42 expressed in the tooth germ of the mice at E13.5,E14.5 and E16.5;the CDC42 expression at E 18.5 was reduced compared with E13.5,E14.5 and E16.5;CDC42 mainly expressed in the odontoblasts and ameloblasts of the tooth germ of the mice at PN1 and PN5;PAR3 weakly expressed in the tooth germ of the mice at E13.5 and E14.5,and it was increased at E16.5 and E18.5.At PN1 and PN5,the expressions of PAR3 were decreased compared with E18.5.Conclusion:CDC42 and PAR3 partieipat in the mouse tooth development;during the early stage of tooth germ development,they may be involved in the proliferation and migration of mouse dental germ;during the late stage,CD42 and PAR3 may be involved in the differentiation of the odontoblasts and the ameloblasts,especially in the establishment and maintenance of cell polarity.