Objective:Blood-brain barrier is the key barrier of brain in the innate immune. It can prevent the harmful substances from the blood into the brain. In order to keep the brain in a relatively stable environment and maintain the normal function of the nervous system, it can also pump harmful substances or excess substances outside the brain selectively. Among them, brain microvascular endothelial cell tissue is a key part in the blood-brain barrier's function. The number of the patients with central nervous system ( CNS) diseases increased year by year. The therapeutic drug is usually inhibited by the blood-brain barrier and is difficult to work. Therefore, how to modify the drug and to make it easier to cross the blood brain barrier is the key point to cure CNS. At present, more than 95% research focus only on how nano drugs can enter the cell, the way and efficiency to enter the cell and the research of effect of nano drug etc. For the process of drug carrier in endocytosis, intracellular transport and release and regulation of research are rarely reported. Clathrin and P-glycoprotein are related protein in endo-cytosis and exocytosis with nano drug. Clathrin is located on the plasma membrane. It participates in endocytosis of some nutrients, and maybe the entry into the cell of some drugs. P-glycoprotein is located in the membrane of cer-ebral capillary endothelial cells. It can efflux drugs relying on ATP. Although there is a certain understanding of the cell in the inner swallow and efflux. But the process of the liposome drug is not clear. To solve the above prob-lems, using colloidal gold liposome nano materials to trace liposome's transport and regulation mechanism in brain microvascular endothelial cells, and study endocytosis, release, distribution and regulation mechanism of nano lipo-somes in brain microvascular. The solution of this problem can guide to construct reasonable drug carrier, and look forward to clarifing the molecular basis and mechanism of nano drug carriers across the BBB. This work has impor-tant theoretical and practical significance for the development and application of liposomes in the future. Results:For untreated cerebral microvascular endothelial cells, the cells incubated with colloidal gold liposomes can uptake of liposome colloidal gold, and with the extension of time, there are gold colloids in the plasma membrane, endo-plasmic reticulum, Golgi apparatus and lysosomes in order, and finally colloidal gold liposome exports out of the cell. For cerebral microvascular endothelial cells treated by sodium azide, compared with untreated cells, the cells incubated with colloidal gold liposomes, cannot be observed liposome colloidal gold in them. For cerebral microvas-cular endothelial cells treated by reserpine, the cells incubated with colloidal gold liposomes, compared with un-treated cells, colloidal gold liposome cannot export out of the cell. Conclusions:The uptake of liposomes in brain microvascular endothelial cells require clathrin's participation. The excretion of liposomes from brain microvascular endothelial cells require P-glycoprotein's participation. After colloidal gold liposome entering brain microvascular endothelial cells, it moves into the endoplasmic reticulum, Golgi apparatus and lysosomes in order. Finally colloi-dal gold liposome exports out of the cell.

Tendon-bone junctions (TBJs) are frequently injured, especially in athletic settings. Healing of TBJ injuries is slow and is often repaired with scar tissue formation that compromises normal function. This study explored the feasibility of using kartogenin (KGN), a biocompound, to enhance the healing of injured TBJs. We first determined the effects of KGN on the proliferation and chondrogenic differentiation of rabbit bone marrow stromal cells (BMSCs) and patellar tendon stem/progenitor cells (PTSCs) in vitro. KGN enhanced cell proliferation in both cell types in a concentration-dependent manner and induced chondrogenic differentiation of stem cells, as demonstrated by high expression levels of chondrogenic markers aggrecan, collagen II and Sox-9. Besides, KGN induced the formation of cartilage-like tissues in cell cultures, as observed through the staining of abundant proteoglycans, collagen II and osteocalcin. When injected into intact rat patellar tendons in vivo, KGN induced cartilage-like tissue formation in the injected area. Similarly, when KGN was injected into experimentally injured rat Achilles TBJs, wound healing in the TBJs was enhanced, as evidenced by the formation of extensive cartilage-like tissues. These results suggest that KGN may be used as an effective cell-free clinical therapy to enhance the healing of injured TBJs.