Remote Manipulation of Ligand Nano-Oscillations Regulates Adhesion and Polarization of Macrophages in Vivo.

Macrophages play crucial roles in various immune-related responses, such as host defense, wound healing, disease progression, and tissue regeneration. Macrophages perform distinct and dynamic functions in vivo, depending on their polarization states, such as the pro-inflammatory M1 phenotype and pro-healing M2 phenotype. Remote manipulation of the adhesion of host macrophages to the implants and their subsequent polarization in vivo can be an attractive strategy to control macrophage polarization-specific functions but has rarely been achieved. In this study, we grafted RGD ligand-bearing superparamagnetic iron oxide nanoparticles (SPIONs) to a planar matrix via a long flexible linker. We characterized the nanoscale motion of the RGD-bearing SPIONs grafted to the matrix, in real time by in situ magnetic scanning transmission electron microscopy (STEM) and in situ atomic force microscopy. The magnetic field was applied at various oscillation frequencies to manipulate the frequency-dependent ligand nano-oscillation speeds of the RGD-bearing SPIONs. We demonstrate that a low oscillation frequency of the magnetic field stimulated the adhesion and M2 polarization of macrophages, whereas a high oscillation frequency suppressed the adhesion of macrophages but promoted their M1 polarization, both in vitro and in vivo. Macrophage adhesion was also temporally regulated by switching between the low and high frequencies of the oscillating magnetic field. To the best of our knowledge, this is the first demonstration of the remote manipulation of the adhesion and polarization phenotype of macrophages, both in vitro and in vivo. Our system offers the promising potential to manipulate host immune responses to implanted biomaterials, including inflammation or tissue reparative processes, by regulating macrophage adhesion and polarization.

[Effects of xuefu zhuyu decoction on antioxidant and drug-metabolizing enzymes in liver of rats].

Xuefu Zhuyu decoction (XFZYD) is a famous traditional Chinese medicine (TCM) formula, is widely used in the treatment of cardiovascular and cerebrovascular diseases in China over one hundred years. But its effect on antioxidant and drug-metabolizing enzymes are unknown. This study was to observe the effects of Xuefu Zhuyu decoction (XFZYD) on the activities of antioxidant and drug metabolism enzymes (DMEs) in liver of rats. Male SD rats, treated with XFZYD at the dosage of 3.51, 7.02 and 14.04 g x kg(-1) per day for 15 days, serum were collected, tissue fluid, cytosols and microsomes isolated from liver tissues were prepared by centrifugation according to the standard procedure, the activities of antioxidant enzymes and drug-Metabolizing Enzymes were determined by UV-V is spectrophotometer. In serum, the activities of AST was not significantly affected by the treatment with XFZYD, at the high- est dose, the levels of ALT, Cr and BUN were significantly decreased (P < 0.05). GPX were significantly increased at the dose of 7.02, 14.04 g x kg(-1) (P < 0.05), CAT were significantly increased at the highest dose (P < 0.05). T-SOD was not significantly af- fected by this treatment. In the liver tissue, GPX was significantly increased at the dose of 3.51, 7.02 g x kg(-1) (P < 0.05), GST, CAT and T-SOD were not significantly affected following this treatment. In cytosols, GST was significantly increased at the dose of 3.51 g x kg(-1) (P < 0.05), T-SOD was remarkable induced at the dose of 3.51 and 7.02 g x kg(-1) (P < 0.05). In microsomes, XFZYD had no significant effect on Cytochromeb5, NADPH-Cytochrome P450 reductase, CYP3A, CYP2E1 and UGT, XFZYD significantly in- duced GST at the dose of 3.51 and 7.02 g x kg(-1) (P < 0.05), and the level of GSH were significantly increased by XFZYD at the dose of 3.51, 7.02 and 14.04 g kg(-1) (P < 0.05). These findings suggest XFZYD can induce the activities of GPX, CAT, SOD, GST and increase GSH level in liver of rats, which indicate XFZYD may have detoxification and antioxidant functions.

Exploring hydrological controls on dissolved organic carbon export dynamics in a typical flash flood catchment using a process-based model.

The dynamics of dissolved organic carbon (DOC) export from headwater catchments are of critical importance for the global carbon balance and are driven by complex runoff processes. Most previous studies have used statistical relationships between runoff and DOC concentration to estimate DOC export dynamics. Thus, the coupling mechanisms between runoff generation and DOC export dynamics at the process level were obscured in the fitting parameters and have rarely been addressed. In this study, high-frequency (hourly) discharge and DOC export from a typical flash flood experimental headwater catchment with an area of 1.8 km2 were simulated using a process-based model (INCA-C). The results showed that the INCA-C model successfully captured the hourly dynamics of both discharge and DOC concentrations with a Nash-Sutcliffe efficiency (NSE) of 0.47-0.81 and 0.28-0.70 among moderate events and 0.81-0.85 and 0.19-0.90 among extreme events, respectively. The DOC was exported with distinct concentration dynamics, fluxes, and contributions from the four flow pathways under different storm intensities. At higher intensities, the DOC fluxes were exported by subsurface flows, particularly from shallow organic soil, with greater peaks and shorter time-to-peaks. Exported DOC is primarily sourced from subsurface runoff from the mineral layer (73 %-77 %) during moderate events, whereas it is primarily sourced from subsurface runoff from the organic layer (61 %-79 %) during extreme events. The two contrasting contributions suggest that hydrological pathway controls and DOC dynamic patterns can shift owing to runoff generation influenced by storm intensity. The distinct and variable controls of different flow pathways on DOC export highlight the need to explain the role of hydrology in regulating DOC storm exports through process-based modelling.

Administration of allogeneic mesenchymal stem cells in lengthening phase accelerates early bone consolidation in rat distraction osteogenesis model.

BACKGROUND: Distraction osteogenesis (DO) is a surgical technique to promote bone regeneration which may require long duration for bone consolidation. Bone marrow-derived mesenchymal stem cells (MSCs) have been applied to accelerate bone formation in DO. However, the optimal time point for cell therapy in DO remains unknown. This study sought to determine the optimal time point of cell administration to achieve early bone consolidation in DO. We hypothesized that the ratio of circulating MSCs to peripheral mononuclear cells and the level of cytokines in serum might be indicators for cell administration in DO. METHODS: Unilateral tibial osteotomy with an external fixator was performed in adult Sprague Dawley rats. Three days after osteotomy, the tibia was lengthened at 0.5 mm/12 h for 5 days. At first, 5 rats were used to analyze the blood components at 6 different time points (3 days before lengthening, on the day lengthening began, or 3, 6, 10, or 14 days after lengthening began) by sorting circulating MSCs and measuring serum levels of stromal cell-derived factor 1 (SDF-1) and interleukin 1ß. Then, 40 rats were used for cell therapy study. A single dose of 5 × 105 allogeneic MSCs was locally injected at the lengthening site on day 3, 6, or 10 after lengthening began, or 3 doses of MSCs were injected at the three time points. Sequential X-ray radiographs were taken weekly. Endpoint examinations included micro-computed tomography analysis, mechanical testing, histomorphometry, and histology. RESULTS: The number of circulating MSCs and serum level of SDF-1 were significantly increased during lengthening, and then decreased afterwards. Single injection of MSCs during lengthening phase (on day 3, but not day 6 or 10) significantly increased bone volume fraction, mechanical maximum loading, and bone mineralization of the regenerate. Triple injections of MSCs at three time points also significantly increased bone volume and maximum loading of the regenerates. CONCLUSION: This study demonstrated that bone consolidation could be accelerated by a single injection of MSCs during lengthening when the ratio of peripheral MSCs to mononuclear cells and the serum SDF-1 presented at peak levels concurrently, suggesting that day 3 after lengthening began may be the optimal time point for cell therapy to promote early bone consolidation.

PLGA/ß-TCP composite scaffold incorporating salvianolic acid B promotes bone fusion by angiogenesis and osteogenesis in a rat spinal fusion model.

Spinal disorders often require surgical treatment called spinal fusion to restore a stabilized spine where bone grafts are implanted for the fusion of adjacent vertebras. In this study, we developed a bioactive composite scaffold incorporated with salvianolic acid B (SB), an active component extracted from Danshen. This study aimed to evaluate the effects of SB-incorporated porous scaffold on spinal fusion models. The composite scaffolds composed of poly (lactic-co-glycolic acid) and tricalcium phosphate (PLGA/ß-TCP) were fabricated with low-temperature rapid prototyping technique, which incorporated SB at low (SB-L), middle (SB-M), high (SB-H) doses, and pure PLGA/ß-TCP as blank control (Con). The release profile of SB from the scaffolds was determined by high performance liquid chromatography. Osteoconductive and osteoinductive properties of the scaffolds were reflected by the osteogenic differentiation ability of rat primary mesenchymal stem cells. The angiogenesis was determined by the forming of tube-like structures resembling capillaries using endothelial cell line (EA hy9.26). A well-established spinal fusion model was used to evaluate the in vivo bony fusion. Animals were transplanted with scaffolds, or autografts from iliac crest as positive controls. Micro-computed tomography (CT) analysis, CT-based angiography, manual palpation test, histomorphometry, and histology were performed after 8 weeks of transplantation. Results revealed that incorporated SB was steadily released from the scaffolds. The aliquot of released SB promoted osteogenesis and angiogenesis in vitro in a dose-dependent manner. In animal study, a dose-dependent effect of SB on new bone formation, mineral apposition rate, and vessel density within the scaffold were demonstrated. Manual palpation test showed little numerical improvement in fusion rate when compared with the blank controls. In summary, our results suggested that SB-incorporated PLGA/ß-TCP composite scaffold could enhance bony fusion through the promotion of osteogenesis and angiogenesis.