As a novel fluorescent nanomaterial,quantum dots (QDs) have a prospect for wide application. However , the adverse effects of QDs have become a concern among and more researchers. The toxic actions of QDs in vivo are closely associated with the biotransport and bio?transformation of QDs,which can be affected by the exposure pathways,exposure dose,surface modification and the particle size. Among them,the exposure pathways can affect the absorption and distribution of QDs in vivo,the exposure dose can affect the metabolism and excretion,thus influencing the distribution of QDs in vivo ,the surface modification can affect the distribution ,metabolism and excretion of QDs in vivo,the particle size can affect the absorption,distribution and excretion of QDs in vivo,and larger QDs are more likely to remain in the body and difficult to remove. QDs can enter the body through the circulatory system,get accumulated and degraded in the liver,kidney and other organs. The degraded products can be excerted through excrement and urine under the metabolism in the liver,spleen and kidneys. In addition,QDs can interact with biological macromolecules in the body,causing DNA damage,affecting the function and gene expression level of the liver,kidney,nervous system and other organs,and resulting in pathological and functional damage to tissues and organs.

Objective To study the potential efficacy of transplanted bone marrow-derived mesenchymal stem cells (MSCs) in treating and repairing the acute lung injury in animal models. Methods MSCs were isolated from mouse bone marrow, cultrued and amplified in vitro. The lipopolysaccharide (LPS) was inhaled through postnasal tract to cause acute lung injury in mice and the MSCs labeled by Brdu were administrated via vein into the mice. The migration and differention of the cells were identified by immunostaining and double immunostaining. The pathological changes, pulmonary edema index and the content of IL-1β in lung homogenate were used to accese the therapeutical effect of MSCs. Results The cultured MSCs dispalyed a positive CD44 and a negative CD34. The Brdu-labeled cells were detected in the lungs of the recipient 4 days after transplantation, indicating its origin of MSCs. Theses cells also exhibited characteristics of aveolar epithelials, expressing the cytokeratin-the marker of epithelium. Compared with the injuried ones, the mice treated with MSCs showed a decreased pulmonary edema in-dex and IL-1β content in the lung homogenate. Conclusion These data suggest a therapeutical effects of MSCs in treating and repairing the mouse acute lung injury.

Graphene family nanomaterials(GFNs)are highly popular in the field of bone tissue engineering because of their excellent mechanical properties,biocompatibility,and ability to promote the osteogenic differentiation of stem cells.GFNs play a multifaceted role in promoting the bone regeneration microenvironment.First,GFNs activate the ad-hesion kinase/extracellularly regulated protein kinase(FAK/ERK)signaling pathway through their own micromorphology and promote the expression of osteogenesis-related genes.Second,GFNs adapt to the mechanical strength of bone tis-sue,which helps to maintain osseointegration;by adjusting the stiffness of the extracellular matrix,they transmit the me-chanical signals of the matrix to the intracellular space with the help of focal adhesions(FAs),thus creating a favorable physiochemical microenvironment.Moreover,they regulate the immune microenvironment at the site of bone defects,thus directing the polarization of macrophages to the M2 type and influencing the secretion of relevant cytokines.GFNs also act as slow-release carriers of bioactive molecules with both angiogenic and antibacterial abilities,thus accelerating the repair process of bone defects.Multiple types of GFNs regulate the bone regeneration microenvironment,including scaffold materials,hydrogels,biofilms,and implantable coatings.Although GFNs have attracted much attention in the field of bone tissue engineering,their application in bone tissue regeneration is still in the basic experimental stage.To promote the clinical application of GFNs,there is a need to provide more sufficient evidence of their biocompatibility,elucidate the mechanism by which they induce the osteogenic differentiation of stem cells,and develop more effective form of applications.

Objective: To explore the synergistic effect of silibinin combined with crizotinib on anaplastic lymphoma kinase positive (ALK+ ) non-small cell lung cancer (NSCLC) cells and its mechanism. Methods: H2228 and H3122 cells were treated with silibinin, crizotinib alone or in combination. Cell proliferation was measured by 3-(4, 5-Dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay and colony formation assay. Migration or invasion ability was tested by wound healing assay or transwell assay, respectively. Expressions of E-Cadherin and vimentin protein were examined by immunofluorescence staining. The protein expressions of ALK, p-ALK, E-Cadherin and Vimentin were detected by western blotting.The anti-cancer effect of silibinin combined with crizotinib in vivo was determined by subcutaneously injecting 2×10⁶ H2228 cells into immunodeficient nude mice. Results: The result of MTT assay showed that the cell viability of H2228 or H3122 treated with 100 μmol/L silibinin was (88.38±4.10)% or (72.27±3.62)%, respectively, marginally decreased compared with that of the control. The 50% inhibitory concentration (IC₅₀) of H2228 cells treated with crizotinib alone or combined with 100 μmol/L silibinin was (917.10±7.75) nmol/L or (238.73±7.67) nmol/L, respectively. The IC₅₀ of H3122 cells treated with crizotinib alone or combined with 100 μmol/L silibinin was (472.50±15.70) nmol/L or (206.10±12.01) nmol/L, respectively. The IC_50s of H2228 and H3122 cells were significantly decreased by combined treatment of crizotinib and silibinin compared to crizotinib treatment alone (P<0.01). When compared with the control group, colony forming ratios of H2228 cells were (83.34±2.72)% in 100 μmol/L silibinin treatment group, (69.42±3.06)% in 400 nmol/L crizotinib treatment group and (27.32±1.42)% in combined treatment group. When compared with the control group, colony forming ratios of H3122 cells were (84.45±5.67)% in 100 μmol/L silibinin treatment group, (45.02±5.83)% in 400 nmol/L crizotinib treatment group and (17.43±3.83)% in combined treatment group. Silibinin combined with crizotinib treatment significantly inhibited the colony formation ability of H2228 and H3122 cells (P<0.01). Migration and invasion results showed that combined treatment of crizotinib and silibinin markedly inhibited the migration and invasion ability of H2228 cells (P<0.01). Western blot results indicated that treated with silibinin alone or in combination of crozitinib for 48 hours, the protein level of E-cadherin in H2228 cells was upregulated, while the expressions of p-ALK and vimentin were downregulated, without obvious alteration of ALK protein expression. In the xenograft model, the mean tumor weight was (9.40±2.58)g in crizotinib treatment group and (4.58±1.07)g in the combined treatment group. The inhibitory effect of tumor growth in vivo of combined treatment was significantly superior to that of crizotinib treatment alone (P<0.05). Conclusion Silibinin enhances the inhibitory effect of crizotinib on ALK positive NSCLC cells, which may be associated with suppression of ALK activity and mesenchymal-epithelial transition.