hBcl2 overexpression in BMSCs enhances resistance to myelin debris-induced apoptosis and facilitates neuroprotection after spinal cord injury in rats.

After spinal cord injury (SCI), the accumulation of myelin debris at the lesion exacerbates cell death and hinders axonal regeneration. Transplanted bone marrow mesenchymal stem cells (BMSCs) have been proven to be beneficial for SCI repair, but they are susceptible to apoptosis. It remains unclear whether this apoptotic process is influenced by myelin debris. Here, we constructed rat BMSCs overexpressing human B-cell lymphoma 2 (hBcl2) alone (hBcl2 group), BMSCs overexpressing hBcl2 with an endoplasmic reticulum-anchored segment (hBcl2-cb) (cb group), and a negative control group (NC group) for transplantation in this study. Immunocytochemistry staining validated the successful expression of hBcl2 in BMSCs within the hBcl2 group and cb group. All BMSCs from each group exhibited the ability to phagocytize myelin debris. Nevertheless, only BMSCs derived from the hBcl2 group exhibited heightened resistance to apoptosis and maintained prolonged viability for up to 5 days when exposed to myelin debris. Notably, overexpression of hBcl2 protein, rather than its endoplasmic reticulum-anchored counterpart, significantly enhanced the resistance of BMSCs against myelin debris-induced apoptosis. This process appeared to be associated with the efficient degradation of myelin debris through the Lamp1+ lysosomal pathway in the hBcl2 group. In vivo, the hBcl2 group exhibited significantly higher numbers of surviving cells and fewer apoptotic BMSCs compared to the cb and NC groups following transplantation. Furthermore, the hBcl2 group displayed reduced GFAP+ glial scarring and greater preservation of NF200+ axons in the lesions of SCI rats. Our results suggest that myelin debris triggers apoptosis in transplanted BMSCs, potentially elucidating the low survival rate of these cells after SCI. Consequently, the survival rate of transplanted BMSCs is improved by hBcl2 overexpression, leading to enhanced preservation of axons within the injured spinal cord.

Enantioseparation by zeolitic imidazolate framework-8-silica hybrid monolithic column with sulfobutylether-ß-cyclodextrin as a chiral additive in capillary electrochromatography.

A zeolitic imidazolate framework (ZIF)-8-silica hybrid monolithic column was prepared by one-step sol-gel method. The stationary phase in the monolithic column was characterized by Fourier-transform infrared spectra, X-ray diffraction, thermogravimetric analysis, nitrogen adsorption/desorption, and zeta potential. The results showed that ZIF-8-silica hybrid monolithic materials had abundant functional groups, good crystallinity, large specific surface area, and good thermal stability. A capillary electrochromatography (CEC) chiral separation system was for the first time constructed with ZIF-8-silica hybrid monolithic column and sulfobutylether-ß-cyclodextrin (SBE-ß-CD) as a chiral additive and was applied to separate the selected single and mixed chiral compounds (13 natural amino acids and 5 chiral pesticides). Under the optimized CEC conditions, all the single analytes achieved baseline separation with resolution of 2.14-5.94 and selectivity factor of 1.06-1.49 in less than 6 min, and the mixed amino acids with similar properties were also simultaneously enantioseparated (Rs ≥ 1.82). Relative standard deviations (RSDs) of migration time and column efficiency were lower than 4.26% and did not change significantly after 200 runs, evidencing excellent reproducibility and stability. These results demonstrate that the application of SBE-ß-CD as a chiral additive for ZIF-8-silica hybrid monolithic columns is a promising method for the separation of chiral compounds.

Chiral covalent organic framework-based open tubular capillary electrochromatography column for enantioseparation of selected amino acids and pesticides.

A novel chiral covalent organic framework (CCOF) was synthesized with an imine covalent organic framework TpBD (synthesized via Schiff-base reaction between phloroglucinol (Tp) and benzidine (BD)) modified using (1S)-(+)-10-camphorsulfonyl chloride as chiral ligand by chemical bonding method for the first time, and was characterized by X-ray diffraction, Fourier-transform infrared spectra, X-ray photoelectron spectroscopy, nitrogen adsorption/desorption, thermogravimetry analysis, and zeta-potential. The results revealed that the CCOF had good crystallinity, high specific surface area and good thermal stability. Then, the CCOF was employed as stationary phase in open-tubular capillary electrochromatography (OT-CEC) column (the CCOF-bonded OT-CEC column) for enantioseparation of 21 single chiral compounds (12 natural amino acids including acidic, neutral and basic, 9 pesticides including herbicides, insecticides and fungicides) and simultaneous enantioseparation of mixture amino acids and pesticides with similar structures or properties. Under the optimized CEC conditions, all the analytes reached the baseline separation with high resolutions of 1.67-25.93 and selectivity factors of 1.06-3.49 in 8 min. Finally, the reproducibility and stability of the CCOF-bonded OT-CEC column were measured. Relative standard deviations (RSDs) of retention time and separation efficiency were 0.58-4.57% and 1.85-4.98%, and not obviously changed after 150 runs. These results demonstrate that COFs-modified OT-CEC explore a promising method to separate chiral compounds.

Tocilizumab promotes repair of spinal cord injury by facilitating the restoration of tight junctions between vascular endothelial cells.

BACKGROUND: Our previous study demonstrated that M1 macrophages could impair tight junctions (TJs) between vascular endothelial cells by secreting interleukin-6 (IL-6) after spinal cord injury (SCI). Tocilizumab, as a humanized IL-6 receptor (IL-6R) monoclonal antibody approved for the clinic, has been applied in the treatment of neurological diseases in recent years, but the treatment effect of Tocilizumab on the TJs restoration of the blood-spinal cord barrier (BSCB) after SCI remains unclear. This study aimed to explore the effect of Tocilizumab on the restoration of TJs between vascular endothelial cells and axon regeneration after SCI. METHODS: In this study, the mouse complete spinal cord crush injury model was used, and Tocilizumab was continuously injected intrathecally until the day of sample collection. A PBS injection in the same location was included as a control. At 14 days postinjury (dpi) and 28 dpi, spinal cord tissue sections were examined via tissue immunofluorescence. The Basso Mouse Scale (BMS) scores and footprint analysis were used to verify the effect of Tocilizumab on the recovery of motor function in mice after SCI. RESULTS: We demonstrated that depletion of macrophages has no effect on axon regeneration and motor functional recovery after SCI, but mice subjected to Tocilizumab showed a significant increase in axon regeneration and a better recovery in motor function during the chronic phase after SCI. Moreover, our study demonstrated that at 14 and 28 dpi, the expression of claudin-5 (CLDN5) and zonula occludens-1 (ZO-1) between vascular endothelial cells was significantly increased and the leakage of BSCB was significantly reduced in the injured core after daily intrathecal injection of Tocilizumab. Notably, the infiltration of CD68+ macrophages/microglia and the formation of fibrotic scar were decreased in the injured core after Tocilizumab treatment. Tocilizumab treatment could effectively reduce the IL-6 expression in macrophages in the injured core. CONCLUSION: The application of Tocilizumab to antagonize IL-6R can effectively reduce the expression of IL-6 in macrophages and facilitate TJs restoration of the BSCB, which is beneficial for axon regeneration and motor functional recovery after SCI. Hence, Tocilizumab treatment is a potential therapeutic strategy for SCI.

A chiral fluorescent COF prepared by post-synthesis modification for optosensing of imazamox enantiomers.

We report a post-synthesis modification for the preparation of a novel chiral fluorescent covalent organic framework (COF) for selective recognization of imazamox enantiomers. In this study, chiral COF was firstly synthesized via a Schiff-base reaction between 2,5-dihydroxyterephthalaldehyde (Dha) and 1,3,5-tris(4-aminophenyl)benzene (Tab) followed by a nucleophilic substitution using (1S)-(+)-10-camphorsulfonyl chloride as chiral modifier. The resulting regular spherical chiral COF Dha Tab not only presented the high optical efficiency, strong covalent bond structure, good crystallinity, large specific surface area but also showed the specific enantioselectivity and quick identification for imazamox enantiomers among five pesticide enantiomers (S/R-imazamox, acephate, acetochlor, propisochlor and metalaxyl). The detection limits for S- and R-imazamox were 4.20 µmol/L and 3.03 µmol/L, respectively. Meanwhile, the enantiomeric excess value (5.30 %) manifested that the chiral COF Dha Tab had the strong adsorption ability to imazamox enantiomers and more higher affinity for R-imazamox. This chiral fluorescent COF opened up a new way for the recognition of enantiomers.

Myelin Debris Impairs Tight Junctions and Promotes the Migration of Microvascular Endothelial Cells in the Injured Spinal Cord.

Clearance of myelin debris caused by acute demyelination is an essential process for functional restoration following spinal cord injury (SCI). Microvascular endothelial cells, acting as "amateur" phagocytes, have been confirmed to engulf and degrade myelin debris, promoting the inflammatory response, robust angiogenesis, and persistent fibrosis. However, the effect of myelin debris engulfment on the function of endothelial tight junctions (TJs) remains unclear. Here, we demonstrate that myelin debris uptake impairs TJs and gap junctions of endothelial cells in the lesion core of the injured spinal cord and in vitro, resulting in increased permeability and leakage. We further show that myelin debris acts as an inducer to regulate the endothelial-to-mesenchymal transition in a dose-dependent manner and promotes endothelial cell migration through the PI3K/AKT and ERK signaling pathways. Together, our results indicate that myelin debris engulfment impairs TJs and promotes the migration of endothelial cells. Accelerating myelin debris clearance may help maintain blood-spinal cord barrier integrity, thus facilitating restoration of motor and sensory function following SCI.

Imatinib inhibits pericyte-fibroblast transition and inflammation and promotes axon regeneration by blocking the PDGF-BB/PDGFRß pathway in spinal cord injury.

BACKGROUND: Fibrotic scar formation and inflammation are characteristic pathologies of spinal cord injury (SCI) in the injured core, which has been widely regarded as the main barrier to axonal regeneration resulting in permanent functional recovery failure. Pericytes were shown to be the main source of fibroblasts that form fibrotic scar. However, the mechanism of pericyte-fibroblast transition after SCI remains elusive. METHODS: Fibrotic scarring and microvessels were assessed using immunofluorescence staining after establishing a crush SCI model. To study the process of pericyte-fibroblast transition, we analyzed pericyte marker and fibroblast marker expression using immunofluorescence. The distribution and cellular origin of platelet-derived growth factor (PDGF)-BB were examined with immunofluorescence. Pericyte-fibroblast transition was detected with immunohistochemistry and Western blot assays after PDGF-BB knockdown and blocking PDGF-BB/PDGFRß signaling in vitro. Intrathecal injection of imatinib was used to selectively inhibit PDGF-BB/PDGFRß signaling. The Basso mouse scale score and footprint analysis were performed to assess functional recovery. Subsequently, axonal regeneration, fibrotic scarring, fibroblast population, proliferation and apoptosis of PDGFRß+ cells, microvessel leakage, and the inflammatory response were assessed with immunofluorescence. RESULTS: PDGFRß+ pericytes detached from the blood vessel wall and transitioned into fibroblasts to form fibrotic scar after SCI. PDGF-BB was mainly distributed in the periphery of the injured core, and microvascular endothelial cells were one of the sources of PDGF-BB in the acute phase. Microvascular endothelial cells induced pericyte-fibroblast transition through the PDGF-BB/PDGFRß signaling pathway in vitro. Pharmacologically blocking the PDGF-BB/PDGFRß pathway promoted motor function recovery and axonal regeneration and inhibited fibrotic scar formation. After fibrotic scar formation, blocking the PDGFRß receptor inhibited proliferation and promoted apoptosis of PDGFRß+ cells. Imatinib did not alter pericyte coverage on microvessels, while microvessel leakage and inflammation were significantly decreased after imatinib treatment. CONCLUSIONS: We reveal that the crosstalk between microvascular endothelial cells and pericytes promotes pericyte-fibroblast transition through the PDGF-BB/PDGFRß signaling pathway. Our finding suggests that blocking the PDGF-BB/PDGFRß signaling pathway with imatinib contributes to functional recovery, fibrotic scarring, and inflammatory attenuation after SCI and provides a potential target for the treatment of SCI.

Preparation of a zeolite imidazole skeleton-silica hybrid monolithic column for amino acid analysis via capillary electrochromatography.

We developed a novel, convenient and low-cost one-pot strategy for preparing a zeolitic imidazolate framework-8 (ZIF-8)-silica hybrid monolithic column by adding ZIF-8 directly to a polymer solution of the silica matrix. The simulated stationary phase and monolithic column prepared under optimal conditions were characterized using X-ray diffraction, scanning electron microscopy, Fourier-transform infrared spectroscopy, thermogravimetric analysis nitrogen physisorption and zeta potential. The results obtained confirmed the successful introduction of ZIF-8 into the silica monolithic column, and the prepared monolithic column exhibited good permeability and physicochemical stability. A capillary electrochromatography method was developed based on a ZIF-8-silica hybrid monolithic column through which 15 mixed amino acids, 4 neutral compounds, 4 nipagin esters and 2 chlorinated fungicides were separated in 14, 5, 7 and 6 min, respectively, under optimal conditions. The relative standard deviations retention times and column efficiencies in run-to-run, day-to-day and column-to-column varied in the ranges of 1.90%-2.21%, 2.13%-2.51% and 3.08%-6.65%, respectively, which demonstrated that ZIF-8-silica hybrid monolithic column exhibited satisfactory reproducibility and stability. The incorporation of ZIF-8 into a silica monolithic column is a promising method for preparing novel monolithic columns composed of a metal-organic framework.

Naoxintong capsule limits myocardial infarct expansion by inhibiting platelet activation through the ERK5 pathway.

BACKGROUND: In the clinic, Naoxintong capsule (NXT) has been applied in two level prevention of ischemic disease. However, its mechanism of action requires further study. PURPOSE: This study investigated whether NXT could affect platelet function and activation under ischemic pathological conditions. MATERIALS AND METHODS: Wistar rats were divided into six groups, sham, saline, NXT (250, 500, 1000 mg/kg), and aspirin group (10 mg/kg). For the pre-treatment assays, MI model was established after pre-administration of saline, NXT-L, NXT-M, NXT-H, and aspirin respectively for 14 days, and after surgery, there were no continuous treatments. For the post-treatment assay, rats were orally administered for 3 days after MI. FeCl3-induced thrombosis model was applied to determine the thrombus wet weight. Bleeding time was used to assess the ability of the platelets to develop a hemostatic plug. RESULTS: NXT decreased infarct size, decreased LDH, CK, and CK-MB values, and improved cardiac function. NXT inhibited platelets activation through reducing CD62P-positive platelets and inhibited infarct expansion by decreasing the number of CD45-positive cells and the amount of MMP9 secreted into the heart tissue. Mechanistically, NXT inhibited platelets activation through decreasing ROS levels, decreasing ERK5 phosphorylation, and increasing RAC1 phosphorylation in MI rats. Pre-treatment with NXT decreased thrombus formation and had normal bleeding times. CONCLUSION: NXT showed obviously preventive effects, which was associated with negative control of platelet activation. The above results provide a basis for clinically expanding application of NXT.

Fibrotic Scar After Spinal Cord Injury: Crosstalk With Other Cells, Cellular Origin, Function, and Mechanism.

The failure of axonal regeneration after spinal cord injury (SCI) results in permanent loss of sensorimotor function. The persistent presence of scar tissue, mainly fibrotic scar and astrocytic scar, is a critical cause of axonal regeneration failure and is widely accepted as a treatment target for SCI. Astrocytic scar has been widely investigated, while fibrotic scar has received less attention. Here, we review recent advances in fibrotic scar formation and its crosstalk with other main cellular components in the injured core after SCI, as well as its cellular origin, function, and mechanism. This study is expected to provide an important basis and novel insights into fibrotic scar as a treatment target for SCI.

Naoxintong restores collateral blood flow in a murine model of hindlimb ischemia through PPARδ-dependent mechanism.

ETHNOPHARMACOLOGICAL RELEVANCE: Naoxintong (NXT) is a compound preparation that is widely used in patients with cardiovascular and cerebrovascular diseases. AIM OF STUDY: The aim of this study is to investigate the protective mechanism of NXT on the mice model of peripheral vascular disease (PAD). MATERIALS AND METHODS: In the study, hindlimb ischemia was induced by ligation of femoral artery on the right leg of mice. After surgery, the mice were administrated with saline solution, 10 mg/kg/d simvastatin and 700 mg/kg/d NXT for 4 weeks. The blood flow perfusion was measured by laser Doppler perfusion imaging system. Histological and immunofluorescent staining was used to determine muscle recovery, capillary density, tissue vascular endothelial growth factor (VEGF), phosphorylated-Akt (p-Akt) and phosphorylated-endothelial nitric oxide synthase (p-eNOS) expression. Terminal deoxynucleotidyl transferased UTP nick end labeling (TUNEL) was performed to detect the apoptosis of myocytes in hindlimb. The autophagy-associated gene expression and peroxisome proliferator-activated receptors (PPARs) expression were measured by Quantitative Real-Time Reverse Transcription Polymerase Chain Reaction (qRT-PCR). Western blotting was performed to detect the expressions of light-chain 3 (LC3), VEGF, p-Akt, p-eNOS and PPARs. The EMSA experiment was performed to figure out whether PPARδ could directly bind to the predicted PPRE motif of VEGF. RESULTS: NXT treatment significantly accelerated perfusion recovery and reduced tissue injury in mice muscle. Apoptosis and autophagy were decreased within the ischemic muscle of NXT-treated mice. Quantification of vessels in hindlimb muscles provided evidences that NXT promoted angiogenesis in peripheral ischemia. In addition, results from western blotting and immunofluorescent staining suggested NXT induced angiogenesis via VEGF/Akt/eNOS signaling pathway. More interestingly, NXT specifically increased the expression of PPARδ in both mRNA and protein levels. EMSA results showed that PPARδ associated with PPRE site of VEGF promoter, suggesting that NXT-induced VEGF expression is mediated, at least in part, by PPARδ. CONCLUSION: In conclusion, the present study implicated that the restoration of hindlimb blood perfusion and recovery of limb functions were improved in NXT-treated mice with significant improvement of angiogenesis mediated by PPARδ-VEGF-Akt-eNOS axis as well as attenuation of autophagy and apoptosis. These results expand knowledge about the beneficial effects of NXT in angiogenesis and blood flow recovery. It might provide insight into the PPARδ regulating neovascularization in hindlimb ischemia and identify NXT as a potent new compound used for the treatment of peripheral vascular disease.

Aucubin promotes angiogenesis via estrogen receptor beta in a mouse model of hindlimb ischemia.

Aucubin (AU) is an iridoid glycoside that has been shown to display estrogenic properties and has various pharmacological effects. Herein, we described the angiogenic properties of AU. In the study, hindlimb ischemia was induced by ligation of femoral artery on the right leg of ovariectomized mice. AU treatment significantly accelerated perfusion recovery and reduced tissue injury in mice muscle. Quantification of CD31-positive vessels in hindlimb muscles provided evidences that AU promoted angiogenesis in peripheral ischemia. In addition, results from quantitative PCR and western blot suggested AU induced angiogenesis via vascular endothelial cell growth factor (VEGF)/Akt/endothelial nitric oxide synthase (eNOS) signaling pathway. More interestingly, AU's angiogenic effects could be completely abolished in estrogen receptor beta (ERß) knockout mice. In conclusion, the underlying mechanisms were elucidated that AU produced pro-angiogenic effects through ERß-mediated VEGF signaling pathways. These results expand knowledge about the beneficial effects of AU in angiogenesis and blood flow recovery. It might provide insight into the ERß regulating neovascularisation in hindlimb ischemia and identify AU as a potent new compound used for the treatment of peripheral vascular disease.

Naoxintong inhibits myocardial infarction injury by VEGF/eNOS signaling-mediated neovascularization.

ETHNOPHARMACOLOGICAL RELEVANCE: Naoxintong capsules (NXT), a traditional Chinese Medical preparation, are widely used for treatment of cardiovascular diseases, while the mechanism is still unclear. MATERIALS AND METHODS: Myocardial infarction (MI) was induced by ligation of the left coronary artery in mice. Echocardiographic measurements were performed to do physiological assessments of left ventricle (LV) function. Histological and immunohistochemical staining was used to determine infarct size, capillary density, tissue endothelial nitric oxide synthase (eNOS) expression. Bone Marrow Transplantation (BMT) model and flow cytometric (FCM) analyses were applied to assay endothelial progenitor cells (EPCs) mobilization. Quantitative Real-Time Reverse Transcription Polymerase Chain Reaction (qRT-PCR), Western blotting and enzyme-linked immunosorbent assay (ELISA) were performed to detect the expressions of vascular endothelial growth factor (VEGF), kinase domain region (KDR), phosphorylated-Akt (p-Akt), phosphorylated-eNOS (p-eNOS). RESULTS: NXT administration reduced myocardium fibrosis and increased myocardium capillary density in response to MI. NXT increased circulating Sca1+/ Fetal liver kinase 1 (Flk1)+ mononuclear cells (MNCs) and soluble Kit ligand (sKitL) of bone marrow (BM) in response to MI. In mice transplanted with green fluorescent protein (GFP) BM cells, NXT increased the numbers of GFP-positive cells at the border zone of the ischemic region in MI-induced mice. NXT increased the numbers of eNOS-expressing BM-derived cells in tissues, which was involved in increased the expressions of VEGF, KDR, p-eNOS, p-Akt in the myocardium. CONCLUSION: NXT-mediated recovery in MI-induced mice was involved in mobilization and incorporation of bone marrow-derived EPCs/circulating angiogenic cells (CACs) leading to enhancement of neovascularization via VEGF/eNOS signaling.

[Preliminary investigation on mechanism of Naoxintong capsule's preventive treatment of cardio-cerebrovascular disease based on serum proteomics].

Naoxintong capsule has beneficial effects for activating blood circulation, dispersing blood stasis and dredging collateral. It is widely used in the treatment of coronary heart disease, angina pectoris, stroke and cardiovascular disease. However, the pharmacodynamic basis and possible mechanism of its preventive effects are not clear. In this study, 10 male and 10 female C57BL/6 mice were used, and were randomly divided into the control group (saline) and Naoxintong group. Adaptively fed for 7 days in common conditions, mice were given Naoxintong capsule or saline for 3 days via intragastric administration. Serum was collected from 6 mice in each group 1 h after the last administration. Serum proteins were prepared to do two-dimensional gel electrophoresis. Then image analysis and mass spectrometry detection were carried out to screen and identify the differentially expressed proteins and make bioinformatics analysis. It was found that 24 differentially expressed proteins between Naoxintong group and control group. Compared with the control group, 12 proteins were increased, and 12 were decreased. The proteins were involved in apoptosis signal pathway and vascular endothelial growth factor signal transduction pathway, in which vasohibin-1 is a negative feedback regulation factor in angiogenesis. Western blot showed that the expression of vasohibin-1 in Naoxintong group was reduced, which is consistent with the result in two-dimensional electrophoresis. Serum proteins expression is different between Naoxintong and control groups. The targets of these differentially expressed proteins include endothelial cells, inflammatory cells and platelets. The changes on proteins showed that Naoxintong capsule may ameliorate coronary heart disease and ischemic cerebrovascular disease, and provide potential biological markers to prevent ischemic disease.

[Effect of Naoxintong capsule on endothelial progenitor cell mobilization and homing following bone marrow transplantation in a mouse hind limb ischemia model].

Endothelial progenitor cells (EPCs) are precursor cells of endothelial cells. Signal molecules produced by ischemia and hypoxia can promote mobilization of bone marrow EPCs to peripheral circulation and formation of novel blood vessels in tissues that are damaged during heart attack. Naoxintong capsule (NXT) has the functions of promoting blood circulation, removing blood stasis, promoting the circulation of qi and relieving pain. The various components in NXT have protective effects on blood vessels and can effectively improve the symptoms of ischemia. However, its effect on EPCs is not clear. To study the intervention effect of NXT on mobilization and homing of peripheral blood EPCs, green fluorescent protein (GFP) transgenic mice were used for bone marrow transplantation (BMT) and then unilateral hind limb ischemia model (UHLI) were constructed. For BMT, wild-type ICR mice were irradiated by CS137 and then injected with 4×106 bone marrow cells isolated from GFP mice. The bone marrow reconstitution of recipients was assessed by quantification of GFP bone marrow-derived cells (BMDC) from transplanted mice 4 weeks after BMT. The UHLI model was duplicated by ligating femoral artery and divided into three groups: the model group, the NXT group (model+NXT) and the positive control group (model+simvastatin). Flow cytometry was used to detect the proportion of GFP positive cells and the peripheral blood EPCs levels at 1, 3, 7, 14 days before and after surgery. Ischemic tissue of gastrocnemius muscle was excised at 3 and 7 days after operation for immunofluorescence staining to detect the number of GFP+ cells. The bone marrow chimerism was achieved at day 28 after BMT. There was no significant difference in the percentage of GFP positive cells between BMT mice and GFP transgenic mice. NXT and simvastatin could significantly increase the number of peripheral blood EPCs 1,3 days after surgery. Three and seven days after operation, the number of homing EPCs was significantly higher in NXT group and positive control group than that in model group (P<0.001). In conclusion, NXT can obviously promote the mobilization and homing of EPCs.