Yongxing Zhang

Correlational Analysis of neck/shoulder Pain and Low Back Pain with the Use of Digital Products, Physical Activity and Psychological Status among Adolescents in Shanghai

Purpose This study investigates the neck/shoulder pain (NSP) and low back pain (LBP) among current high school students in Shanghai and explores the relationship between these pains and their possible influences, including digital products, physical activity, and psychological status. Methods An anonymous self-assessment was administered to 3,600 students across 30 high schools in Shanghai. This questionnaire examined the prevalence of NSP and LBP and the level of physical activity as well as the use of mobile phones, personal computers (PC) and tablet computers (Tablet). The CES-D (Center for Epidemiological Studies Depression) scale was also included in the survey. The survey data were analyzed using the chi-square test, univariate logistic analyses and a multivariate logistic regression model. Results Three thousand sixteen valid questionnaires were received including 1,460 (48.41%) from male respondents and 1,556 (51.59%) from female respondents. The high school students in this study showed NSP and LBP rates of 40.8% and 33.1%, respectively, and the prevalence of both influenced by the student’s grade, use of digital products, and mental status; these factors affected the rates of NSP and LBP to varying degrees. The multivariate logistic regression analysis revealed that Gender, grade, soreness after exercise, PC using habits, tablet use, sitting time after school and academic stress entered the final model of NSP, while the final model of LBP consisted of gender, grade, soreness after exercise, PC using habits, mobile phone use, sitting time after school, academic stress and CES-D score. Conclusions High school students in Shanghai showed high prevalence of NSP and LBP that were closely related to multiple factors. Appropriate interventions should be implemented to reduce the occurrences of NSP and LBP.

PPARγ forms a bridge between DNA methylation and histone acetylation at the C/EBPα gene promoter to regulate the balance between osteogenesis and adipogenesis of bone marrow stromal cells

The balance between osteogenesis and adipogenesis of bone marrow stromal cells is impaired in many human diseases. Knowledge of how to fine‐tune this balance is of medical importance. CCAAT/enhancer binding protein α (C/EBPα) has been shown to regulate the balance between osteogenesis and adipogenesis of C3H10T1/2 cells, with epigenetic modifications of the C/EBPα promoter playing an important role. The present study aimed to elucidate the underlying molecular mechanisms. The results showed that peroxisome proliferator‐activated receptor γ (PPARγ) binds the −1286 bp/−1065 bp region of the C/EBPα promoter to activate C/EBPα expression during osteogenesis and adipogenesis of C3H10T1/2 cells. DNA hypermethylation in the −1286 bp/−1065 bp region, observed at the terminal stage of osteogenesis, prevented PPARγ binding, and then histone deacetylase 1 (HDAC1) occupied this region to reduce the level of histone acetylation. We regulated the balance between osteogenesis and adipogenesis of mouse bone marrow stromal cells through modulation of DNA methylation and histone acetylation status. In addition, in bone marrow stromal cells from the glucocorticoid‐induced osteoporosis (GIO) mouse, hypomethylation of CpG sites, higher binding of PPARγ, acetylated histones 3 and 4, and reduced binding of HDAC1 in the −1286 bp/−1065 bp region of C/EBPα promoter were observed, compared with normal mice. This study provides a deeper insight into the molecular mechanisms underlying the balance between osteogenesis and adipogenesis regulated by C/EBPα in synergy with PPARγ, and suggests a molecular model for how DNA methylation and histone acetylation are linked by PPARγ to regulate differentiation of bone marrow stromal cells.

Construction of polydopamine-coated gold nanostars for CT imaging and enhanced photothermal therapy of tumors: an innovative theranostic strategy

The advancement of biocompatible nanoplatforms with dual functionalities of diagnosis and therapeutics has been strongly demanded in biomedicine in recent years. In this work, we report the synthesis and characterization of polydopamine (pD)-coated gold nanostars (Au NSs) for computed tomography (CT) imaging and enhanced photothermal therapy (PTT) of tumors. Au NSs were firstly formed via a seed-mediated growth method and then stabilized with thiolated polyethyleneimine (PEI-SH), followed by deposition of pD on their surface. The formed pD-coated Au NSs (Au-PEI@pD NSs) were well characterized. We show that the Au-PEI@pD NSs are able to convert the absorbed near-infrared laser light into heat, and have strong X-ray attenuation properties. Due to the co-existence of Au NSs and pD, the light to heat conversion efficiency of the NSs can be significantly enhanced. These very interesting properties allow them to be used as a powerful theranostic nanoplatform for efficient CT imaging and enhanced phtotothermal therapy of cancer cells in vitro and the xenografted tumor model in vivo. Due to their easy functionalization nature enabled by the coated pD shell, the developed pD-coated Au NSs may be used as a versatile nanoplatform for targeted CT imaging and PTT of different types of cancers.

Composite mesoporous silica nanoparticle/chitosan nanofibers for bone tissue engineering

Electrospinning of inorganic–organic composites into nanofibers has emerged as a new approach for fabricating scaffolds for biomimetically engineered bone tissues. This paper reports novel biomimetic nanocomposite nanofibers composed of mesoporous silica nanoparticles/chitosan (MSN/CTS) prepared by electrospinning. The optimal conditions for electrospinning CTS and MSNs were identified to produce beadless nanofibers without any aggregation of the MSNs. The mechanical properties of the composite scaffolds were analyzed by tensile tests for scaffolds with varying contents of MSNs within CTS fibers. Increasing the MSN content to 10 wt% enhanced the mechanical properties of the composite scaffolds, whereas increasing the content beyond 10 wt% disrupted the polymer chain networks within the CTS nanofibers and weakened the mechanical strength of the fibers. Swelling ratio, shrinkage and biodegradation properties were characterized. MTT, SEM, alkaline phosphatase activity and Alizarin Red staining analysis of osteoblast-cultured scaffolds confirmed the biocompatibility and functionally promoted biomineralization of the composite scaffolds. Thus, the prepared MSN/CTS composite nanofibrous mats are highly promising as local implantable scaffolds for potential bone tissue engineering applications.

Dynamic and distinct histone modifications of osteogenic genes during osteogenic differentiation.

Many skeletal diseases have common pathological phenotype of defective osteogenesis of bone marrow stromal cells (BMSCs), in which histone modifications play an important role. However, few studies have examined the dynamics of distinct histone modifications during osteogenesis. In this study, we examined the dynamics of H3K9/K14 and H4K12 acetylation; H3K4 mono-, di- and tri-methylation; H3K9 di-methylation and H3K27 tri-methylation in osteogenic genes, runt-related transcription factor 2 (Runx2), osterix (Osx), alkaline phosphatase, bone sialoprotein and osteocalcin, during C3H10T1/2 osteogenesis. H3 and H4 acetylation and H3K4 di-methylation were elevated, and H3K9 di-methylation and H3K27 tri-methylation were reduced in osteogenic genes during C3H10T1/2 osteogenesis. C3H10T1/2 osteogenesis could be modulated by altering the patterns of H3 and H4 acetylation and H3K27 tri-methylation. In a glucocorticoid-induced osteoporosis mouse model, we observed the attenuation of osteogenic potential of osteoporotic BMSCs in parallel with H3 and H4 hypo-acetylation and H3K27 hyper-tri-methylation in Runx2 and Osx genes. When H3 and H4 acetylation was elevated, and H3K27 tri-methylation was reduced, the attenuated osteogenic potential of osteoporotic BMSCs was rescued effectively. These observations provide a deeper insight into the mechanisms of osteogenic differentiation and the pathophysiology of osteoporosis and can be used to design new drugs and develop new therapeutic methods to treat skeletal diseases.

Preparation of Laponite Bioceramics for Potential Bone Tissue Engineering Applications

We report a facile approach to preparing laponite (LAP) bioceramics via sintering LAP powder compacts for bone tissue engineering applications. The sintering behavior and mechanical properties of LAP compacts under different temperatures, heating rates, and soaking times were investigated. We show that LAP bioceramic with a smooth and porous surface can be formed at 800°C with a heating rate of 5°C/h for 6 h under air. The formed LAP bioceramic was systematically characterized via different methods. Our results reveal that the LAP bioceramic possesses an excellent surface hydrophilicity and serum absorption capacity, and good cytocompatibility and hemocompatibility as demonstrated by resazurin reduction assay of rat mesenchymal stem cells (rMSCs) and hemolytic assay of pig red blood cells, respectively. The potential bone tissue engineering applicability of LAP bioceramic was explored by studying the surface mineralization behavior via soaking in simulated body fluid (SBF), as well as the surface cellular response of rMSCs. Our results suggest that LAP bioceramic is able to induce hydroxyapatite deposition on its surface when soaked in SBF and rMSCs can proliferate well on the LAP bioceramic surface. Most strikingly, alkaline phosphatase activity together with alizarin red staining results reveal that the produced LAP bioceramic is able to induce osteoblast differentiation of rMSCs in growth medium without any inducing factors. Finally, in vivo animal implantation, acute systemic toxicity test and hematoxylin and eosin (H&E)-staining data demonstrate that the prepared LAP bioceramic displays an excellent biosafety and is able to heal the bone defect. Findings from this study suggest that the developed LAP bioceramic holds a great promise for treating bone defects in bone tissue engineering.

How schooling and lifestyle factors effect neck and shoulder pain? A cross-sectional survey of adolescents in China.

Study Design. A cross-sectional survey by anonymous self-assessment questionnaire was given to 3600 high school students from 30 high schools. Objective. The purpose of this study was to analyze the prevalence of neck and shoulder pain (NSP) and its effects among high school students in Shanghai, China. Summary of Background Data. NSP has become a problem in many countries in recent years among adolescents. No recent studies have estimated the prevalence of NSP in Chinese school populations. Methods. A total of 3600 high school students from all 3 grades chosen from 30 random schools participated in this study. Participants were asked to fill out a questionnaire on NSP and to provide information on demographic items, family factors, schooling, and lifestyles. &khgr;2 tests were used to compare the incidence of NSP, univariate and multivariate logistic regression analyses were used to obtain influencing factors of NSP. Results. In total, 3600 questionnaires were distributed, and 2842 were valid. The cross-sectional prevalence of NSP was 41.1%, with more girls (653 of 1478, i.e., 44.2%) reporting having NSP than boys (514 of 1364, i.e., 37.7%) (odds ratio = 0.764; 95% confidence interval = 0.657–0.888; P < 0.05). The frequency, duration, and degree of NSP in girls were also higher than in boys. For high school years 1, 2, and 3, the incidence of NSP was 40.1%, 40.7%, and 45.4%, respectively. The multivariate logistic regression indicated that sex, family history of NSP, school furniture, long sitting time, computer use, insufficient rest time, sleep time, commuting method, perceived schoolbag weight, and smoking had a significant effect on NSP. Conclusion. The incidence of NSP in high school students in Shanghai is quite high. The occurrence of NSP is related to several factors including sex and school year, as well as some factors related to family, schooling, and lifestyles. Level of Evidence: 3

Epigenetic landscape in PPARγ2 in the enhancement of adipogenesis of mouse osteoporotic bone marrow stromal cell.

Osteoporosis is one of the most prevalent skeletal system diseases; yet, its pathophysiological mechanisms remain elusive. Adipocytes accumulate remarkably in the bone marrow of osteoporotic patients. The potential processes and molecular mechanisms underlying adipogenesis in osteoporotic BMSCs have attracted significant attention as adipocytes and osteoblasts share common precursor cells. Some environmental factors influence bone mass through epigenetic mechanisms; however, the role of epigenetic modifications in osteoporosis is just beginning to be investigated, and there is still little data regarding their involvement. In the current study, we investigated how epigenetic modifications, including DNA methylation and histone modifications, lead to adipogenesis in the bone marrow during osteoporosis. A glucocorticoid-induced osteoporosis (GIO) mouse model was established, and BMSCs were isolated from the bone marrow. Compared with normal BMSCs, osteoporotic BMSCs had significantly increased adipogenesis potential and decreased osteogenesis potential. In osteoporotic BMSCs, PPARγ2 regulatory region DNA hypo-methylation, histone 3 and 4 hyper-acetylation and H3K9 hypo-di-methylation were observed. These epigenetic modifications were involved not only in PPARγ2 expression but also in osteoporotic BMSC adipogenic differentiation potential. We also found that Wnt/β-catenin signal played an important role in the establishment and maintenance of epigenetic modifications at PPARγ2 promoter in osteoporotic BMSCs. Finally, we inhibited adipogenesis and rescued osteogenesis of osteoporotic BMSCs by modulating those epigenetic modifications. Our study provides a deeper insight into the pathophysiology of osteoporosis and identifies PPARγ2 as a new target for osteoporosis therapy based on epigenetic mechanisms.

Enhanced antitumor efficacy of doxorubicin-encapsulated halloysite nanotubes

To improve the antitumor efficacy of doxorubicin (DOX) and provide novel clinical treatment of gastric cancer, halloysite nanotubes (HNTs) loaded with DOX were encapsulated by soybean phospholipid (LIP) and the formed HNTs/DOX/LIP was systematically characterized via different techniques. The in vitro anticancer activity of HNTs/DOX/LIP was examined using an MTT assay. The antitumor efficacy and biocompatibility were monitored by measuring the tumor volume and assessing the blood routine and serum biochemistry using an ectopic implantation cancer model. The results show that when the concentration of HNTs was 3 mg/mL and the concentration of DOX was 1 mg/mL the optimal DOX loading efficiency was as high as 22.01%±0.43%. In vitro drug release behavior study demonstrated that HNTs/DOX/LIP shows a pH-responsive release property with fast drug release under acidic conditions (pH =5.4). MTT assays and in vivo experimental results revealed that HNTs/DOX/LIP exhibits a significantly higher inhibitory efficacy on the growth of mouse gastric cancer cells than free DOX at the same drug concentration. In addition, the life span of tumor-bearing mice in the HNTs/DOX/LIP-treated group was obviously prolonged compared with the control groups. Moreover, HNTs/DOX/LIP possessed excellent hemocompatibility as shown in the blood and histology studies. These findings indicated that the formed HNTs/DOX/LIP possesses higher antitumor efficacy and may be used as a targeted delivery nanoplatform for targeting therapy of different types of cancer cells.

Se@SiO2 nanocomposites suppress microglia-mediated reactive oxygen species during spinal cord injury in rats

Selenium (Se) is an essential trace element with strong antioxidant activity, showing a great prospect in the treatment of spinal cord injury (SCI). However, the narrow gap between the beneficial and toxic effects has limited its further clinical application. In this experiment, we used porous Se@SiO2 nanocomposites (Se@SiO2) modified by nanotechnology as a new means of release control to investigate the anti-oxidative effect in SCI. In vitro Se@SiO2 toxicity, anti-oxidative and anti-inflammatory effects on microglia were assayed. In vivo we investigated the protective effect of Se@SiO2 to SCI rats. Neurological function was evaluated by Basso, Beattie and Bresnahan (BBB). The histopathological analysis, microglia activation, oxidative stress, inflammatory factors (TNF-α, IL-1β and IL-6) and apoptosis were detected at 3 and 14 days after SCI. The favorable biocompatibility of Se@SiO2 suppressed microglia activation, which is known to be associated with oxidative stress and inflammation in vivo and in vitro. In addition, Se@SiO2 improved the rat neurological function and reduced apoptosis via caspase-3, Bax and Bcl-2 pathways in SCI. Se@SiO2 was able to treat SCI and reduce oxidative stress, inflammation and apoptosis induced by microglia activation, which may provide a novel and safe strategy for clinical application.