Comparison of three methods for establishing rat peri-implantitis model / 北京大学学报(医学版)

OBJECTIVE@#To compare the efficiency and effect of establishing rat peri-implantitis model by traditional cotton thread ligation and local injection of Porphyromonas gingivalis lipopolysaccharide (LPS) around the implant, as well as the combination of the two methods.@*METHODS@#Left side maxillary first molars of 39 male SD rats were extracted, and titanium implants were implanted after four weeks of healing. After 4 weeks of implant osseointegration, 39 rats were randomly divided into 4 groups. Cotton thread ligation (n=12), local injection of LPS around the implant (n=12), and the two methods combined (n=12) were used to induce peri-implantitis, the rest 3 rats were untreated as control group. All procedures were conducted under 5% isoflurane inhalation anesthesia. The rats were sacrificed 2 weeks and 4 weeks after induction through carbon dioxide asphyxiation method. The maxilla of the rats in the test groups were collected and marginal bone loss was observed by micro-CT. The gingival tissues around the implants were collected for further real time quantitative PCR (RT-qPCR) analysis, specifically the expression of tumor necrosis factor-alpha (TNF-α) as well as interleukin-1β (IL-1β). The probing depth (PD), bleeding on probing (BOP) and gingival index (GI) of each rat in the experimental group were recorded before induction of inflammation and before death.@*RESULTS@#After 4 weeks of implantation, the osseointegration of implants were confirmed. All the three test groups showed red and swollen gums, obvious marginal bone loss around implants. After 2 weeks and 4 weeks of inflammation induction, PD, GI and BOP of the three test groups increased compared with those before induction, but only BOP was statistically significant among the three test groups (P < 0.05). At the end of 2 weeks of inflammation induction, marginal bone loss was observed at each site in the cotton thread ligation group and the combined group. At each site, the bone resorption in the combined group was greater than that in the cotton thread ligation group, but the difference was not statistically significant (P > 0.05), bone resorption was observed at some sites of some implants in LPS local injection group. At the end of 4 weeks of inflammation induction, marginal bone loss was observed at all sites in each group. The marginal bone loss in the cotton thread ligation group and the combined group was greater than that in the LPS local injection group, and the difference was statistically significant (P < 0.05). At the end of 2 weeks and 4 weeks of induction, the expression of TNF-α and IL-1β in the test groups were higher than those in the control group (P < 0.05).@*CONCLUSION@#Compared with local injection of LPS around the implant, cotton thread ligature and the two methods combined can induce peri-implantitis in rats better and faster.

Advances in research on exosomes as drug delivery vehicles / 药学学报

Exosomes are membranous vesicles that are actively secreted by cells. They can be isolated from various cell culture media and animal body fluids. Exosomes are mainly composed of lipids, proteins and nucleic acids. They have small molecular structure and high biocompatibility with size of 40-100 nm. In addition, exosomes are natural endogenous nanocarriers that can transport lipids, proteins, DNA and RNA. Studies have shown that exosomes play an important role in long-distance communication between cells, in physiological and pathological processes. This article introduces the composition and physiological functions of exosomes, and summarizes the relevant content of exosomes as drug delivery vehicles. The applications of exosomes in central nervous system diseases, especially brain diseases and tumors are summarized.

Nanodrug delivery systems based on drug-phospholipid complex: Research advances / 国际药学研究杂志

Phospholipids are the major components of the biomembrane. Combining the phospholipids and the drugs to form drug-phospholipid complex can improve the solubility, stability and bioavailability of the drugs. On this basis, the nanodrug delivery system, which is constructed with the drug- phospholipid complex as an intermediate carrier, has become a research hot spot in the field of pharmaceutics. This kind of nanodrug delivery system can not only improve the solubility, stability and bioavailability of drugs, but also carry out the targeted drug delivery, decrease the drug dose and reduce the side effects, thereby it is very promising. In this review, we describe the structural composition, characteristics, forming mechanism of the drug-phospholipid complex and the research progresses in a variety of nanodrug delivery systems based on drug-phospholipid complex.