By-Product of the Red Ginseng Manufacturing Process as Potential Material for Use as Cosmetics: Chemical Profiling and In Vitro Antioxidant and Whitening Activities.

Red ginseng (RG), which is obtained from heated Panax ginseng and is produced by steaming followed by drying, is a valuable herb in Asian countries. Steamed ginseng dew (SGD) is a by-product produced in processing red ginseng. In the present study, phytochemical profiling of extracts of red ginseng and steamed ginseng dew was carried out using gas chromatography-mass spectrometry (GC-MS) and rapid resolution liquid chromatography coupled with quadrupole-time-of-flight mass spectrometry (RRLC-Q-TOF-MS) analysis. Additionally, antioxidant activities (DPPH, ·OH, and ABTS scavenging ability) and whitening activities (tyrosinase and elastase inhibitory activity) were analyzed. Phytochemical profiling revealed the presence of 66 and 28 compounds that were non-saponin components in chloroform extracts of red ginseng and steamed ginseng dew (RG-CE and SGD-CE), respectively. Meanwhile, there were 20 ginsenosides identified in n-butanol extracts of red ginseng and steamed ginseng dew (RG-NBE and SGD-NBE). By comparing the different polar extracts of red ginseng and steamed ginseng dew, it was found that the ethyl acetate extract of red ginseng (RG-EAE) had the best antioxidant capacity and whitening effect, the water extract of steamed ginseng dew (SGD-WE) had stronger antioxidant capacity, and the SGD-NBE and SGD-CE had a better whitening effect. This study shows that RG and SGD have tremendous potential to be used in the cosmetic industries.

HSP90 facilitates stemness and enhances glycolysis in glioma cells.

BACKGROUND: Glioma is one of the most commonly occurring malignant brain cancers with high recurrence and mortality. Glioma stem cells (SCs) are a rare sub-group of glioma cells that play a critical role in tumor progression. Heat shock protein 90 (HSP90) is known to promote the stemness of glioma SCs. Here, we investigated the role of HSP90 in glioma SC metabolism, to reveal its potential as a novel therapeutic target. METHODS: Self-renewal assays were used to assess stemness. Cell migration, invasion and viability were measured using Transwell and CCK-8 assays, respectively. Tumor growth was evaluated in xenograft nude mouse models. The expression of known markers of stemness including CD44, A2B5, Oct4, Nestin, Lgr5, Sox2, CD24 were assessed by western blotting. HSP90 expression was assessed by western blotting and immunohistochemistry (IHC). Glucose consumption, lactic acid production and ATP levels were measured using commercially available kits. Extracellular acidification rates (ECAR) were measured using the Seahorse XFe/XF analyzer. RESULTS: HSP90 was upregulated in spheroid cells compared to parental cells. HSP90 facilitated the characteristics of SCs through enhancing self-renewal capacity, glucose consumption, lactic acid production, total ATP, ECAR and glycolysis. 2-DG, an inhibitor of glycolysis, reduced HSP90 expression and inhibited the stemness of glioma cells. CONCLUSIONS: We show that HSP90 accelerates stemness and enhances glycolysis in glioma cells. Inhibition of glycolysis with 2DG prevented stemness. This reveals new roles for HSP90 during glioma progression and highlights this protein as a potential target for much-needed anti-glioma therapeutics.

Outcomes of cardiac surgery in senior aged patients with ventricular dysfunction: analysis of a large national database.

OBJECTIVE: In patients undergoing cardiac surgery, reduced preoperative ejection fraction (EF) and senior age are associated with a worse outcome. As most outcome data available for these patients are mainly from Western surgical populations involving specific surgery types, our aim is to evaluate the real-world characteristics and perioperative outcomes of surgery in senior-aged heart failure patients with reduced EF across a broad range cardiac surgeries. METHODS: Data were obtained from the China Heart Failure Surgery Registry (China-HFSR) database, a nationwide multicenter registry study in mainland China. Multiple variable regression analysis was performed in patients over 75 years old to identify risk factors associated with mortality. RESULTS: From 2012 to 2017, 578 senior-aged (> 75 years) patients were enrolled in China HFSR, 21.1% of whom were female. Isolated coronary bypass grafting (CABG) were performed in 71.6% of patients, 10.1% of patients underwent isolated valve surgery and 8.7% received CABG combined with valve surgery. In-hospital mortality was 10.6%, and the major complication rate was 17.3%. Multivariate analysis identified diabetes mellitus (odds ratio (OR) = 1.985), increased creatinine (OR = 1.007), New York Heart Association (NYHA) Class III (OR = 1.408), NYHA class IV (OR = 1.955), cardiogenic shock (OR, 6.271), and preoperative intra-aortic balloon pump insertion (OR = 3.426) as independent predictors of in-hospital mortality. CONCLUSIONS: In senior-aged patients, preoperative evaluation should be carefully performed, and strict management of reversible factors needs more attention. Senior-aged patients commonly have a more severe disease status combined with more frequent comorbidities, which may lead to a high risk in mortality.

A 3-dimensional-printed left ventricle model incorporated into a mock circulatory loop to investigate hemodynamics inside a severely failing ventricle supported by a blood pump.

Intraventricular blood stasis is a design consideration for continuous flow blood pumps and might contribute to adverse events such as thrombosis and ventricular suction. However, the blood flow inside left ventricles (LVs) supported by blood pumps is still unclear. In vitro experiments were conducted to imitate how the hydraulic performance of an axial blood pump affects the intraventricular blood flow of a severe heart failure patient, such as velocity distribution, vorticity, and standard deviation of velocity. In this study, a silicone model of the LV was constructed from the computed tomography data of one patient with heart failure and was 3D printed. Then, intraventricular flow was visualized by particle image velocimetry equipment within a mock circulation loop. The results showed that the axial blood pump suctions most of the blood in a severely failing LV, there was an altered flow status within the LV, and blood stasis appeared in the central region of the LV. Some blood may be suctioned from the aortic valve to the blood pump because the patient's native heart was severely failing. Blood stasis at the LV center may cause thrombosis in the LV. The vortex flow near the inner wall of the LV can thoroughly wash the left ventricular cavity.

Surgical left atrial appendage occlusion in patients with atrial fibrillation undergoing mechanical heart valve replacement.

BACKGROUND: Surgical left atrial appendage occlusion (SLAAO) may be associated with a lower risk of thromboembolism in patients with atrial fibrillation undergoing cardiac surgery. However, evidence regarding the effectiveness of SLAAO in patients undergoing mechanical heart valve replacement (MHVR) is lacking. Therefore, we aimed to evaluate the association between SLAAO and the cardiovascular outcomes in patients with atrial fibrillation undergoing MHVR. METHODS: We retrospectively analyzed data for 497 patients with atrial fibrillation; 27.6% of the patients underwent SLAAO, and the remainder of the patients did not (No-SLAAO group). The primary outcome was a composite of ischemic stroke, systemic embolism, and all-cause mortality. Cumulative event-free survival rates were estimated using Kaplan-Meier curves, and we performed multivariate Cox analyses to evaluate the association between SLAAO and outcomes. We used one-to-one propensity score matching to balance patients' baseline characteristics, and analyzed 120 matching pairs. RESULTS: Five patients died within 30 days postoperatively, and there were no significant differences between the two groups regarding in-hospital complications (all P > 0.05). After a median follow-up of 14 months, 14 primary events occurred. Kaplan-Meier curves showed no difference in the cumulative incidence of freedom from the primary outcome (log-rank P = 0.830), hemorrhagic events (log-rank P = 0.870), and the secondary outcome (log-rank P = 0.730), between the two groups. Multivariable Cox proportional hazards regression analysis showed no association between SLAAO and any outcome (all P > 0.05). After propensity score matching, cardiopulmonary bypass time and aortic cross-clamp time, and the postoperative length of stay were significantly longer in the SLAAO group (all P < 0.05); results were similar to the unadjusted analyses. CONCLUSIONS: Concomitant SLAAO and MHVR was associated with longer length of stay, and cardiopulmonary bypass time and aortic cross-clamp time, but was not associated with additional protective effects against thromboembolic events and mortality during the 14-month follow-up.

Platelet adhesion emulation: A novel method for estimating the device thrombosis potential of a ventricular assist device.

Device thrombosis inside ventricular assist devices remains a limitation to their long-term clinical use. Thrombosis potential exists in almost all ventricular assist devices because the device-induced high shear stress and vortices can activate platelets, which then aggregate and adhere to the surfaces inside the ventricular assist device. To decrease the device thrombosis potential of long-term use of ventricular assist devices, a methodology entitled platelet adhesion emulation for predicting the thrombosis potential and thrombosis position inside the ventricular assist devices is developed. The platelet adhesion emulation methodology combines numerical simulations with in vitro experiments by correlating the structure of the flow passage components within the ventricular assist device with the platelet adhesion to estimate the thrombosis potential and location, with the goal of developing ventricular assist devices with optimized antithrombotic performance. Platelet adhesion emulation is aimed at decreasing the device thrombus potential of ventricular assist devices. The platelet adhesion emulation effectiveness is validated by simulating and testing an axial left ventricular assist device. The blood velocity relative to the surfaces of the flow passage components is calculated to estimate the platelet adhesion potential, indicating the probability of thrombus formation on the surfaces. Platelet adhesion emulation experiments conducted in a mock circulation loop with pump prototypes show the distribution of platelet adhesion on the surfaces. This methodology of emulating the device thrombosis distribution indicates the potential for improving the component structure and reducing the device thrombosis of ventricular assist devices.

Platelet deposition estimation: A novel method for emulating the pump thrombosis potential of blood pumps.

Pump thrombosis potential exists in most blood pumps and limits their clinical use. To improve the pump thrombosis performance of blood pumps, a method for emulating the platelet deposition on the flow passage component surfaces inside blood pumps was presented and tested. The method emulates the blood platelet deposition, employing laser-induced fluorescence tracing technology. The blood pump was rotated in a mock circulation loop with deionized water filled with fluorescent particles. The component surfaces were then explored via laser. The fluorescent particles were induced by laser and imaged in a charge-coupled device (CCD) camera to show the distribution of fluorescent particles gathering on the blood pump component surfaces. The activated platelet deposition was emulated by fluorescent particle gathering. The experiment showed obvious particle gathering on the interface surfaces and cross-sectional surface (perpendicular to the flow). This platelet deposition estimation (PDE) method can be easily incorporated in the in vitro testing phase to analyze and decrease a pump's thrombosis potential before animal experimentation, thereby reducing the cost of blood pump development. This methodology of emulating blood platelet deposition indicates its potential for improving flow passage component structure and reducing device thrombosis of blood pumps.

Numerical investigation of the influence of a bearing/shaft structure in an axial blood pump on the potential for device thrombosis.

Adverse events caused by flow-induced thrombus formation around the bearing/shaft of an axial blood pump remain a serious problem for axial blood pumps. Moreover, excessive anticoagulation with thrombosis around the bearing potentially increases the risk of postoperative gastrointestinal bleeding. The purpose of this study is to analyze the influence of the bearing structure on the thrombosis potential of an axial blood pump. The bearing/shaft structure was embedded into an axial blood pump numerical model. The numerical simulation and analysis are focused on the low wall shear stresses, recirculation, and residence time close to the bearing region to evaluate the potential for thrombosis around the bearing. Then, the flow field near the blood pump bearing was tested via in vitro particle image velocimetry experiments to verify the numerical results. The simulation results showed that after embedding the bearing/shaft structure a recirculation zone appeared in the outlet guide vane bearing/shaft region, the residence time increased 11-fold in comparison to the pump without the bearing/shaft structure, the scalar shear stress in the shaft surface was less than 7.8 Pa, and the stress accumulation was less than 0.10 Pa s. The numerical results showed that platelets that flow through the bearing region are exposed to significantly lower wall shear stress and a longer residence time, leading to activated platelet adhesion. The reduced stress accumulation and increased time in the bearing region lead to increased platelet activation.

The NK1 receptor antagonist NKP608 inhibits proliferation of human colorectal cancer cells via Wnt signaling pathway.

BACKGROUND: Neurokinin1 (NK1) receptor has played a vital role in the development of tumor. However, NKP608 as a NK1 receptor antagonist whether has the effect of the resistance of colorectal cancer is still unclear. Thereby, in this study, we investigated the role of NKP608 on human colorectal cancer and explored the underlying mechanism. METHODS: The cell proliferation of colorectal cancer cells was detected by cell counting kit-8 (CCK8) assay, cell migration and invasion were assessed by transwell assay, the apoptotic ratio of cells was assessed by Annexin V-fluorescein isothiocyanate/propidium iodide stained and flow cytometry. The involvement of molecular mechanisms was examined by western blot. RESULTS: In this study, we found that NKP608 inhibited the proliferation, migration/invasion of HCT116 cells. In addition, NKP608 reduced expressions of Wnt-3a, ß-catenin, Cyclin D1, and (vascular endothelial growth factor) VEGF while induced expression of E-Cadherin. Furthermore, flow cytometry analyzed that NKP608 induced apoptosis of HCT116 cells, consistently, western blotting detecting of apoptosis-related proteins revealed that NKP608 downregulated Bcl-2 while upregulated Bax and Active-Caspase-3. CONCLUSIONS: Taken together, our results demonstrated that NKP608 inhibited colorectal cancer cell proliferation, migration and invasion via suppressing the Wnt/ß-catenin signaling pathway. Therefore, NKP608 might represent a promising therapeutic agent in the treatment of colorectal cancer.

The NK1 receptor antagonist NKP608 inhibits proliferation of human colorectal cancer cells via Wnt signaling pathway

BACKGROUND: Neurokinin1 (NK1) receptor has played a vital role in the development of tumor. However, NKP608 as a NK1 receptor antagonist whether has the effect of the resistance of colorectal cancer is still unclear. Thereby, in this study, we investigated the role of NKP608 on human colorectal cancer and explored the underlying mechanism. METHODS: The cell proliferation of colorectal cancer cells was detected by cell counting kit-8 (CCK8) assay, cell migration and invasion were assessed by transwell assay, the apoptotic ratio of cells was assessed by Annexin V-fluorescein isothiocyanate/propidium iodide stained and flow cytometry. The involvement of molecular mechanisms was examined by western blot. RESULTS: In this study, we found that NKP608 inhibited the proliferation, migration/invasion of HCT116 cells. In addition, NKP608 reduced expressions of Wnt-3a, ß-catenin, Cyclin D1, and (vascular endothelial growth factor) VEGF while induced expression of E-Cadherin. Furthermore, flow cytometry analyzed that NKP608 induced apoptosis of HCT116 cells, consistently, western blotting detecting of apoptosis-related proteins revealed that NKP608 downregulated Bcl-2 while upregulated Bax and Active-Caspase-3. CONCLUSIONS: Taken together, our results demonstrated that NKP608 inhibited colorectal cancer cell proliferation, migration and invasion via suppressing the Wnt/ß-catenin signaling pathway. Therefore, NKP608 might represent a promising therapeutic agent in the treatment of colorectal cancer.

Surgical Treatment of Secondary Tricuspid Regurgitation: Insight Derived From Annulus Sizes and Tethering Distances.

BACKGROUND: The main goal of this study was to explore the feasibility of stratifying patients with secondary tricuspid regurgitation (TR) into different risk levels, and to compare the surgical outcomes of patients within different risk levels who underwent different tricuspid valve repair (TVP) approaches. METHODS: One hundred and one patients with left-sided valvular disease underwent either left-sided valvular replacement or repair, and 79 patients underwent concomitant TVP. Depending upon their tricuspid annulus diameter and tethering distances, the patients were assessed using 4 risk levels. The different surgical approaches were used in patients within different risk levels. RESULTS: Among the 101 patients, there were 32 patients within risk level I, 28 within risk level II, 20 within risk level III, 21 within risk level IV. In the first risk level, the patients with untreated tricuspid valves had no or mild TR after surgery. In the second and third risk levels, the patients treated with a modified De Vega procedure had mild TR at follow-up. In the fourth risk level, the patients treated with undersized annuloplasty rings exhibited an improved outcome. CONCLUSIONS: The evaluation of both tricuspid annular diameter and tethering distance may help clinicians to stratify patients with secondary TR into different risk levels as a means of choosing an optimal TVP approach. The application of a modified De Vega procedure or an undersized annuloplasty ring in patients within appropriate risk level could improve the treatment for secondary TR.

Genome sequence of type strain Paenibacillus polymyxa DSM 365, a highly efficient producer of optically active (R,R)-2,3-butanediol.

Paenibacillus polymyxa DSM 365, an efficient producer of (R,R)-2,3-butanediol, is known to show the highest production titer and productivity reported to date. Here, the first draft genome sequence of this promising strain may provide the genetic basis for further insights into the molecular mechanisms underlying the production of (R,R)-2,3-butanediol with high optical purity and at a high titer. It will also facilitate the design of rational strategies for further strain improvements, as well as construction of artificial biosynthetic pathways through synthetic biology for asymmetric synthesis of chiral 2,3-butanediol or acetoin in common microbial hosts.

[Variation of soil respiration and its underlying mechanism in grasslands of northern China].

Soil respiration is one of the most important variables in terrestrial ecosystem progresses and global carbon cycle, and determines the CO2 flux from soil to atmosphere. Soil respiration also has great implications for predicting regional and even global carbon cycle changes under the background of global climate change. We measured respiration rates of soil samples collected from northern China grassland transect by short term incubation experiment in laboratory. Results showed that soil respiration rates increased with mean annual precipitation (MAP) from west sites to east sites, ranging from 0.35 to 2.09 µg CO2-C · g(-1) · h(-1). The variation range of soil respiration rates were 0.35-0.73 µg CO2-C · g(-1) · h(-1) with MAP < 100 mm, 0.57-0.98 µg CO2-C · g(-1) · h(-1) with MAP between 100 mm and 200 mm and 0.83-2.10 µg CO2-C · g(-1) · h(-1) with MAP > 300 mm, respectively. Soil respiration had a significant positive relationship with MAP, aboveground biomass, soil organic carbon and nitrogen content, while had a negative relationship with mean annual temperature and soil pH. Analysis of boosted regression tree showed that the predictors accounted for the explained variation included MAP (25.5%), aboveground biomass (23.6%), soil organic carbon content (18.3%) and soil organic nitrogen content (12.5%), and soil pH and mean annual tem- perature only explained 10.8% and 9.2% of the total variation, respectively.

[Impact of smoking and smoking cessation on long-term outcome of patients after coronary artery bypass grafting].

OBJECTIVE: To determine the impact of smoking behaviors on long-term outcomes of coronary artery bypass grafting (CABG). METHODS: We conducted this survey in 2541 consecutive patients who underwent CABG in Fu Wai hospital from January 1, 2004 to December 30, 2005. The preoperative and postoperative smoking habits were obtained. The patients were divided into never smokers and ever smokers. The ever smokers were further divided into the current smokers who smoked before and after CABG and former smokers who stopped smoking before CABG, quitters who stopped smoking after CABG. Death, major adverse cardiovascular or cerebrovascular events and angina pectoris were observed. The relative risk of adverse events in different patients were analyzed by univariate and multivariate Cox analysis. RESULTS: The patients were followed up for 4.27 to 6.41 years (average 5.09 years). After CABG, the percentage of persistent smoking patients was 22.1%. After adjusting baseline characteristics, relative risk for tumor related death (RR: 2.38, 95%CI: 1.06 - 5.36), major adverse cardiovascular or cerebrovascular events (RR: 1.26, 95%CI: 1.01 - 1.57) and angina pectoris (RR: 1.29, 95%CI: 1.04 - 1.59) were significantly higher in ever smokers than in never smokers. Similarly, relative risk of death from all causes (RR: 2.60, 95%CI: 1.53 - 4.46), cardiac death (RR: 2.51, 95%CI: 1.32 - 4.78), tumor cause death (RR: 5.12, 95%CI: 2.08 - 12.59), major adverse cardiovascular or cerebrovascular events (RR: 1.83, 95%CI: 1.42 - 2.34) and angina pectoris (RR: 1.69, 95%CI: 1.33 - 2.16) were also significantly higher in current smokers than in never smokers. Outcome was similar between patients who stopped smoking and never smokers (all P > 0.05). CONCLUSIONS: Smoking prevalence is still high in patients after CABG in China. Persistent smoking is associated with higher rates of mortality and morbidity after CABG while smoking cessation is associated with reduction of morbidity and mortality in patients after CABG.

Alteration of parasympathetic/sympathetic ratio in the infarcted myocardium after Schwann cell transplantation modified electrophysiological function of heart: a novel antiarrhythmic therapy.

BACKGROUND: Neural remodeling after myocardial infarction (MI) may cause fatal ventricular arrhythmia. Schwann cells (SCs), which are important for neurogenesis, are dramatically reduced after MI. We investigated the feasibility of modifying nervous system regeneration after MI and the efficacy by which it may prevent ventricular arrhythmia following SC transplantation. METHODS AND RESULTS: Immediately after creation of MI, syngenic Lewis rats were randomized into cell transplantation (n=80) and control groups (n=72). SCs were isolated from sciatic nerves, and 5×10(6) cells were intramyocardially injected into the infarct region. Expression levels of myocardial nerve growth factor, vascular endothelial growth factor, growth-associated protein 43, connexin 43, and laminin in the SC group were significantly higher than control at 7 and 14 days after cell transplantation. Immunohistochemical staining illustrated increases in sympathetic and parasympathetic nerves in both groups. However, SC transplantation significantly increased the parasympathetic/sympathetic ratio at 14 days after cell injection. Dynamic electrocardiography and programmed electric stimulation were also performed. The SCs significantly decreased the low-/high-frequency ratio and arrhythmia score of programmed electric stimulation-induced ventricular arrhythmia at 2 weeks after cell injection. However, SCs did not restore heart function. CONCLUSIONS: Transplanted SCs in the infarcted myocardium secrete multiple biological molecules, which alter the ratio of parasympathetic/sympathetic nerve density to normalize irritable myocardium. SC transplantation might be a novel cell-based antiarrhythmic therapy following MI.

Low level laser irradiation precondition to create friendly milieu of infarcted myocardium and enhance early survival of transplanted bone marrow cells.

We suggested that low-level laser irradiation (LLLI) precondition prior to cell transplantation might remodel the hostile milieu of infarcted myocardium and subsequently enhance early survival and therapeutic potential of implanted bone marrow mesenchymal stem cells (BMSCs). Therefore, in this study we wanted to address: (1) whether LLLI pre-treatment change the local cardiac micro-environment after myocardial infarction (MI) and (2) whether the LLLI preconditions enhance early cell survival and thus improve therapeutic angiogenesis and heart function. MI was induced by left anterior descending artery ligation in female rats. A 635 nm, 5 mW diode laser was performed with energy density of 0.96 J/cm(2) for 150 sec. for the purpose of myocardial precondition. Three weeks later, qualified rats were randomly received with LLLI precondition (n= 26) or without LLLI precondition (n= 27) for LLLI precondition study. Rats that received thoracotomy without coronary ligation were served as sham group (n= 24). In the cell survival study, rats were randomly divided into 4 groups: serum-free culture media injection (n= 8), LLLI precondition and culture media injection (n= 8), 2 million male BMSCs transplantation without LLLI pre-treatment (n= 26) and 2 million male BMSCs transplantation with LLLI precondition (n= 25) group, respectively. Vascular endothelial growth factor (VEGF), glucose-regulated protein 78 (GRP78), superoxide dismutase (SOD) and malondialdehyde (MDA) in the infarcted myocardium were evaluated by Western blotting, real-time PCR and colorimetry, respectively, at 1 hr, 1 day and 1 week after laser irradiation. Cell survival was assayed with quantitative real-time PCR to identify Y chromosome gene and apoptosis was assayed with transferase-mediated dUTP end labelling staining. Capillary density, myogenic differentiation and left ventricular function were tested by immunohistochemistry and echocardiography, respectively, at 1 week. After LLLI precondition, increased VEGF and GRP78 expression, as well as the enhanced SOD activity and inhibited MDA production, was observed. Compared with BMSC transplantation and culture media injection group, although there was no difference in the improved heart function and myogenic differentiation, LLLI precondition significantly enhanced early cell survival rate by 2-fold, decreased the apoptotic percentage of implanted BMSCs in infarcted myocardium and thus increased the number of newly formed capillaries. Taken together, LLLI precondition could be a novel non-invasive approach for intraoperative cell transplantation to enhance cell early survival and therapeutic potential.

In vitro effects of low-level laser irradiation for bone marrow mesenchymal stem cells: proliferation, growth factors secretion and myogenic differentiation.

BACKGROUND AND OBJECTIVES: Bone marrow derived mesenchymal stem cells (BMSCs) have shown to be an appealing source for cell therapy and tissue engineering. Previous studies have confirmed that the application of low-level laser irradiation (LLLI) could affect the cellular process. However, little is known about the effects of LLLI on BMSCs. The aim of this study was designed to investigate the influence of LLLI at different energy densities on BMSCs proliferation, secretion and myogenic differentiation. STUDY DESIGN/MATERIALS AND METHODS: BMSCs were harvested from rat fresh bone marrow and exposed to a 635 nm diode laser (60 mW; 0, 0.5, 1.0, 2.0, or 5.0 J/cm(2)). The lactate dehydrogenase (LDH) release was used to assess the cytotoxicity of LLLI at different energy densities. Cell proliferation was evaluated by using 3-(4, 5-dimethylithiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) and 5-bromo-2'-deoxyuridine (BrdU) assay. Production of vascular endothelial growth factor (VEGF) and nerve growth factor (NGF) were measured by enzyme-linked immunosorbent assay (ELISA). Myogenic differentiation, induced by 5-azacytidine (5-aza), was assessed by using immunocytochemical staining for the expression of sarcomeric alpha-actin and desmin. RESULTS: Cytotoxicity assay showed no significant difference between the non-irradiated group and irradiated groups. LLLI significantly stimulated BMSCs proliferation and 0.5 J/cm(2) was found to be an optimal energy density. VEGF and NGF were identified and LLLI at 5.0 J/cm(2) significantly stimulated the secretion. After 5-aza induction, myogenic differentiation was observed in all groups and LLLI at 5.0 J/cm(2) dramatically facilitated the differentiation. CONCLUSIONS: LLLI stimulates proliferation, increases growth factors secretion and facilitates myogenic differentiation of BMSCs. Therefore, LLLI may provide a novel approach for the preconditioning of BMSCs in vitro prior to transplantation.