Inhibition of bromodomain-containing protein 4 ameliorates oxidative stress-mediated apoptosis and cartilage matrix degeneration through activation of NF-E2-related factor 2-heme oxygenase-1 signaling in rat chondrocytes.

During the progression of osteoarthritis, dysregulation of extracellular matrix (ECM) anabolism, abnormal generation of reactive oxygen species, and proteolytic enzymes have been shown to accelerate the degradation process of cartilage. The purpose of the current study was to investigate the functional role of bromodomain-containing protein 4 (BRD4) in hydrogen peroxide (H2 O2 )-stimulated chondrocyte injury and delineate the underlying molecular mechanisms. We observed that the expression BRD4 was markedly elevated in rat chondrocytes after H2 O2 stimulation. Additionally, inhibition of BRD4 using small interfering RNA or JQ1 (a selective potent chemical inhibitor) led to repression of H2 O2 -induced oxidative stress, as revealed by a decrease in the reactive oxygen species production accompanied by a decreased malondialdehyde content, along with increased activities of antioxidant markers superoxide dismutase, catalase, and glutathione peroxidase on exposure of chondrocytes to H2 O2 . Meanwhile, depletion of BRD4 led to repress the oxidative stress-induced apoptosis of chondrocytes triggered by H2 O2 accompanied by an increase in the expression of anti-apoptotic Bcl-2 and a decrease in the expression of pro-apoptotic Bax and caspase 3 as well as attenuated caspase 3 activity. Moreover, knockdown of BRD4 or treatment with JQ1 markedly attenuated ECM deposition, reflected in a marked upregulation of proteoglycans collagen type II and aggrecan as well as downregulation of ECM-degrading enzymes matrix metalloproteinase 13 and A disintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS-5). More importantly, inhibition of BRD4-activated NF-E2-related factor 2 (Nrf2)-heme oxygenase-1 signaling. Mechanistically, the protective effect of BRD4 inhibition on H2 O2 -stimulated apoptosis and cartilage matrix degeneration was markedly abrogated by Nrf2 depletion. Altogether, we concluded that the protective effect of BRD4 inhibition against oxidative stress-mediated apoptosis and cartilage matrix degeneration occurred through Nrf2-heme oxygenase-1 signaling, implying that BRD4 inhibition may be a more effective therapeutic strategy against osteoarthritis.

TRAIL gene 1595C/T polymorphisms contribute to the susceptibility and severity of intervertebral disc degeneration: a data synthesis.

BACKGROUND: Studies have investigated the correlation between tumor necrosis factor related apoptosis-inducing ligand (TRAIL) gene polymorphisms and the susceptibility and severity of intervertebral disc degeneration (IDD), but the results were inconsistent. To evaluate the specific relationship, we performed a meta-analysis to clarify the controversies. METHODS: Four databases were searched, and the pooled results were presented as odds ratios (ORs) with 95% confidence intervals (CIs). RESULTS: Three case-control studies from Han Chinese were included (565 cases and 427 controls). All the included studies reported TRAIL 1595C/T gene polymorphisms. The recessive model (CC vs. CT + TT) was the optimal model, which demonstrated a significant relationship between 1595C/T polymorphisms and increased IDD risk (OR = 2.18, 1.45 to 3.27, P = 0.000). No significant heterogeneity was found in the recessive model (I2 = 48.6%, P = 0.143). Patients with lower grade IDD had more genotypes or alleles including 1595TT genotype (grade II vs. grade III: OR = 2.12, 1.18 to 3.83, P = 0.012; grade III vs. grade IV: OR = 2.59, 1.29 to 5.22, P = 0.007) and 1595 T allele (grade II vs. grade III: OR = 1.91, 1.43 to 2.55, P = 0.000; grade II vs. grade IV: OR = 2.46, 0.94 to 1.76, P = 0.000). CONCLUSIONS: There is a significant relationship between 1595C/T polymorphisms and the susceptibility and severity of IDD in Han Chinese. Patients with lower grade IDD had higher frequency of the 1595TT genotype and 1595 T allele.

A controlled case study of the relationship between environmental risk factors and apoptotic gene polymorphism and lumbar disc herniation.

To explore the etiologic role of apoptosis-related genes, environmental risk factors, and their interaction in the occurrence of lumbar disk herniation (LDH), a controlled case study was performed with 128 LDH patients and 132 age- and sex-matched controls. Matrix-assisted laser desorption/ionization, time-of-flight mass spectrometry assay was used to analyze the genotype of nine polymorphism sites in three genes, including Fas -1377G/A rs2234767, Fas -670G/A rs1800682, Fas rs2147420, Fas rs2296603, Fas rs7901656, Fas rs1571019, Fas ligand (FasL) -844C/T rs763110, caspase 9 (CASP9) -1263A>G rs4645978, and CASP9 -712C>T rs4645981. The patients and controls showed similar age and sex, but had significant differences in lumbar load, bed type, amateur sports, and leisure activities (P < 0.05). The correlation analysis revealed that polymorphism of FasL -844C/T (rs763110) and CASP9 -1263A>G (rs4645978) had a significant correlation with LDH, indicating that the genotypes of FasL -844C/T TT and CASP9 -1263A>G GG are probably high-risk genotypes for LDH. The results of environment-gene interaction analysis revealed that, in LDH, the interaction of the FasL -844TT genotype and level III to IV lumbar load was consistent with the ultramultiplying model, and the interaction of the CASP9 rs4645978 GG genotype and level III to IV lumbar load was consistent with the submultiplicative model. Therefore, the risk of LDH was determined by both environmental and genetic risk factors, and the mechanisms of interactions between different genotypes and environmental factors also differed.

MALDI-TOF-MS serum protein profiling for developing diagnostic models and identifying serum markers for discogenic low back pain.

BACKGROUND: The identification of the cause of chronic low back pain (CLBP) represents a great challenge to orthopedists due to the controversy over the diagnosis of discogenic low back pain (DLBP) and the existence of a number of cases of CLBP of unknown origin. This study aimed to develop diagnostic models to distinguish DLBP from other forms of CLBP and to identify serum biomarkers for DLBP. METHODS: Serum samples were collected from patients with DLBP, chronic lumbar disc herniation (LDH), or CLBP of unknown origin, and healthy controls (N), and randomly divided into a training set (n = 30) and a blind test set (n = 30). Matrix-assisted laser desorption ionization time-of-flight mass spectrometry was performed for protein profiling of these samples. After the discriminative ability of two most significantly differential peaks from each two groups was assessed using scatter plots, classification models were developed using differential peptide peaks to evaluate their diagnostic accuracy. The identity of peptides corresponding to three representative differential peaks was analyzed. RESULTS: The fewest statistically significant differential peaks were identified between DLBP and CLBP (3), followed by CLBP vs. N (5), DLBP vs. N (9), LDH vs. CLBP (20), DLBP vs. LDH (23), and LDH vs. N (43). The discriminative ability of two most significantly differential peaks was poor in classifying DLBP vs. CLBP but good in classifying DLBP vs. LDH. The accuracy of models for classification of DLBP vs. CLBP was not very high in the blind test (forecasting ability, 67.24%; sensitivity, 70%), although a higher accuracy was observed for classification of DLBP vs. LDH and LDH vs. N (forecasting abilities, ~90%; sensitivities, >90%). A further investigation of three representative differential peaks led to the identification of two peaks as peptides of complement C3, and one peak as a human fibrinogen peptide. CONCLUSIONS: Our findings benefit not only the diagnosis of CLBP but also the understanding of the differences between different forms of DLBP. The ability to distinguish between different causes of CLBP and the identification of serum biomarkers may be of great value to diagnose different causes of DLBP and predict treatment efficacy.

Reduced apoptosis correlates with enhanced autophagy in synovial tissues of rheumatoid arthritis.

OBJECTIVE: Defective apoptosis contributes to the massive synovial hyperplasia in rheumatoid arthritis (RA), but the mechanism is largely unknown. To investigate the reasons for the reduced apoptosis in RA synovium, we analyzed autophagy and its relationship to apoptosis in synovial tissues from RA and osteoarthritis (OA) patients. METHODS: Synovial tissues were obtained from seven RA and 12 OA patients undergoing knee replacement surgery. Apoptosis was detected by the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and staining for p85 fragment of PolyADP-ribose polymerase (PARP). Autophagy was determined by immunoblotting for the autophagic markers Beclin-1 and LC3. MicroRNA-30a (miR-30a), which targets Beclin-1, was measured by real-time RT-PCR. The interplay between autophagy and apoptosis was determined via Spearman's correlation analysis. RESULTS: In comparison with OA, the synovial tissues from RA displayed decreased TUNEL-positive nuclei (P < 0.01). In contrast, Beclin-1 and LC3 were overexpressed in the synovial lining layers of RA, which was correlated with decreased levels of miR-30a. Moreover, there was a significant reverse relationship between apoptosis and autophagy in RA synovial tissues (P < 0.01 and r = -0.8937). CONCLUSION: The impaired apoptosis in RA synovium might result from increased autophagy, which in turn could be due to the deregulation of miRNA-30a.

Negative pressure technology enhances bone regeneration in rabbit skull defects.

BACKGROUND: Bone is a slowly regenerating tissue influenced by various physiological processes, including proliferation, differentiation, and angiogenesis, under the control of growth factors. Shortening this healing time is an important and popular clinical research focus in orthopedics. Negative pressure can stimulate angiogenesis, improve blood circulation, promote granulation tissue growth and accelerate tissue wound healing. We sought to determine whether negative pressure could reduce bone healing time in a rabbit cranial defect model. METHODS: Four symmetrical holes (diameter, 3.5 mm) were drilled into the skulls of 42 New Zealand white rabbits, with two holes in each parietal bone. For each rabbit, the two sides were then randomly assigned into experimental and control groups. Using negative pressure suction tubes, experimental holes were treated with -50 kPa for 15 minutes, four times per day, whereas the control holes remained untreated. After 4 weeks, the negative pressure suction tubes were removed. At 2, 4, 6 and 8 weeks, three-dimensional (3D) reconstruction computed tomography (CT), X-ray radiopacity, and two-photon absorptiometry were used to evaluate new bone formation. Histological changes were determined by hematoxylin and eosin (H.E) staining. At weekly intervals until 6 weeks, the mRNA expression levels of vascular endothelial growth factor (VEGF) and bone morphogenetic protein (BMP)-2 were evaluated by RT-PCR. A paired student's t-test was employed to compare X-ray radiopacity and bone density measurements between the experimental and control groups. RESULTS: 3D-reconstruction CT showed that new bone regeneration in the experimental group was greater than that in the control group at 4 and 6 weeks. At these time points, the experimental group presented with higher X-ray radiopacity and increased bone density (P < 0.05) as compared with the control group. Cartilage islands and new bone were observed by H.E staining at 2 weeks in the experimental group. By 6 weeks, the new bone had matured into lamellar bone in the experimental group. RT-PCR results showed that VEGF and BMP-2 were highly expressed in the experimental group as compared with control. CONCLUSIONS: Intermittent negative pressure can promote the regeneration of bone possibly by enhancing the expression of VEGF and BMP-2.

Acute abdomen after vertebroplasty-A rare complication.

Introduction: In recent years, as the concept of minimally invasive treatment has been accepted by the majority of patients, the application of percutaneous vertebroplasty in osteoporotic vertebral compression fractures has gradually increased, and research on the adverse complications of bone cement leakage has gradually deepened. Case: Here, we report a rare case of acute pancreatitis after vertebroplasty. The patient had no previous history of pancreatitis and presented with obvious abdominal pain after vertebroplasty. Abdominal CT examination revealed that the leaking bone cement penetrated the anterior wall of the L1 vertebral body into the diaphragm, and the heat released by the polymerization reaction caused inflammation and damage to the adjacent pancreas, resulting in poor blood flow to the pancreatic tissue and leading to acute pancreatitis. Early postoperative symptomatic treatment was given to the patient, and the corresponding symptoms were gradually relieved. During postoperative follow-up, the leaking cement did not degrade, but the patient had no symptoms. Conclusion: Lesions of adjacent organs caused by bone cement leakage are rare, and clinicians often ignore the association between such complications and vertebroplasty. This case report will provide guidance and a reference for clinicians.

Comparison of Three Common Intervertebral Disc Discectomies in the Treatment of Lumbar Disc Herniation: A Systematic Review and Meta-Analysis Based on Multiple Data.

OBJECTIVE: Due to recent developments and the wide application of percutaneous transforaminal discectomy (PTED), we herein compare it with microendoscopic discectomy (MED) and traditional open surgery (OD) through surgical indicators and postoperative outcomes to evaluate the advantages and disadvantages of minimally invasive surgery PTED. METHODS: This systematic review and meta-analysis was conducted in line with PRISMA guidelines (PROSPERO2018: CRD42018094890). We searched four English and two Chinese databases from the date of their establishment to May 2022. Randomized controlled trials and case-control studies of PTED versus MED or PTED versus OD in the treatment of lumbar disc herniation were retrieved. RESULTS: A total of 33 studies with 6467 cases were included. When comparing MED with PTED, the latter had less intraoperative blood loss, smaller incision, shorter postoperative bed times, shorter hospitalization times, better postoperative visual analogue scale (VAS) for low back pain, and postoperative dysfunction index (Oswestry Disability Index, ODI) and higher recurrence rates and revision rates. However, operation times, postoperative VAS leg scores and complications, and successful operation rates were similar in both groups. Comparison of PTED with OD revealed in the former less intraoperative blood loss and smaller incision, shorter postoperative bed times, shorter hospitalization times, shorter operation times, and higher recurrence rates and revision rates. Nonetheless, comprehensive postoperative VAS scores, VAS leg pain scores, VAS low back pain, ODI and incidence of complications, and successful operation rates were similar between the two groups. CONCLUSIONS: The therapeutic effect and safety of PTED, MED and OD in the treatment of lumbar disc herniation were comparable. PTED had obvious advantages in that it is minimally invasive, with rapid recovery after surgery, but its recurrence rates and revision rates were higher than MED and OD. Therefore, it is not possible to blindly consider replacing MED and OD with PTED.

Association between Caspase-9 promoter region polymorphisms and discogenic low back pain.

Caspase-9 (CASP-9) is an initiator caspase protease for apoptosis, and plays an important role in the development and progression of lumbar disc disease (LDD). The expression and/or activity of CASP-9 are significantly enhanced in the degenerated disc. The polymorphism in the promoter region of CASP-9 enhances the transcriptional activity of this gene, thereby modulating the susceptibility to LDD. The current study investigated the relationship between the CASP-9 -1263A/G (rs4645978) and -712C/T (rs4645981) polymorphisms and discogenic low back pain (LBP). The CASP-9 -1263A/G and -712C/T genotypes in this study were defined by polymerase chain reaction in 154 patients with discogenic LBP and 216 controls that were frequency-matched by age, gender, and occupation. The results showed that the CASP-9 -1263 GG genotype, compared with the AA and AG genotypes [odds ratio (OR) = 1.997, 95% confidence interval (95% CI) = 1.216-3.279, p = 0.006] or the AA genotype (OR = 2.760, 95% CI = 1.464-5.203, p = 0.002), is associated with a significant increased risk of discogenic LBP, but the -712 TT or TT and CT genotypes do not contribute to discogenic LBP compared with the CC genotype (OR = 0.547, 95% CI = 0.200-1.494, p = 0.234 and OR = 0.669, 95% CI = 0.439-1.021, p = 0.062, respectively). These results indicated that the CASP-9 -1263A/G polymorphism is associated with a high risk of discogenic LBP.

Biomechanical effects of reconstruction of the posterior structures after laminectomy with an individualized poly-ether-ether-ketone (PEEK) artificial lamina.

BACKGROUND: Laminectomy is a traditional method for treating lumbar diseases; however, the destruction of the posterior structures may cause postoperative symptoms. An individualized poly-ether-ether-ketone (PEEK) artificial lamina was designed to reconstruct the posterior structures after laminectomy. This study aimed to explore the biomechanical effects of reconstruction of the posterior structures with an individualized PEEK artificial lamina using validated finite element models. OBJECTIVE: To examine the biomechanical effects of individualized PEEK artificial lamina on postlaminectomy lumbar. METHODS: A finite element (FE) model of L3-5 was developed based on computed tomography images. Four surgical models (laminectomy, artificial lamina alone, ligament reconstruction, and osseointegration) were constructed, representing different stages of L4 artificial lamina implantation. The range of motion (ROM), intradiscal pressure (IDP), stresses in the annulus fibrosus at the surgical level and cephalad adjacent level, and stresses in the artificial lamina and screws were measured. RESULTS: The ROM, IDP, and stresses in the annulus fibrosus of the different artificial lamina models decreased compared to those of the laminectomy model at both surgical and adjacent levels for all motion patterns, most notably in the osseointegration model. In addition, the results of the stresses in the implants showed that the artificial lamina could enhance the lumbar isthmus and disperse the abnormally concentrated stresses after laminectomy. CONCLUSION: The application of a PEEK artificial lamina has the potential to stabilize the postlaminectomy lumbar spine and prevent adjacent segment disease (ASD) and iatrogenic lumbar deformities, resulting in a reduction in the incidence of post-lumbar surgery syndrome.

Effect of negative pressure on human bone marrow mesenchymal stem cells in vitro.

The aim of this study was to determine how low-intensity intermittent negative pressure affects the differentiation and proliferation of human mesenchymal stem cells (MSCs), as well of OPG and OPGL mRNA expression in MSCs. MSCs were isolated from adult marrow using the density gradient separation method, passaged for three generations, and divided into the vacuum group, which was administrated at pressure of -50 kPa, for 30 min at a frequency of 2/d, and a control group. The differentiation of MSCs was examined through inverted phase contrast microscopy, measurement of alkaline phosphatase activity, alizarin-red staining, and immunohistochemistry for type I collagen, hypoxia-inducible factor-1alpha (HIF-1a), and vascular endothelial growth factor (VEGF). The MTT assay and flow cytometry were used to measure proliferation and apoptosis. Real-time PCR detected the expression of mRNA from OPG/OPGL. Compared to the control group, there was a decrease in the proliferation of cells in the vacuum group. The number of cells in S phase was reduced by 62.4%, while the rate of apoptosis, the activity of ALP, and calcium release all increased under vacuum conditions. Calcium nodes could be observed through alizarin-red staining, and the expression of collagen type I, VEGF, and HIF-1a were increased significantly. Expression of OPG mRNA was increased and the expression of OPGL mRNA decreased in the vacuum group relative to the control group. In conclusion, low-intensity intermittent negative pressure can inhibit the proliferation of human MSCs, induce differentiation to bone cells, promote the OPG mRNA expression, and reduce OPGL mRNA expression.

Gene expression profiles of disc tissues and peripheral blood mononuclear cells from patients with degenerative discs.

The objective of this study was to analyze gene expression profiles of intervertebral disc samples and peripheral blood mononuclear cells (PBMCs) from patients with degenerative discs using Agilent's Human 1A Oligo microarray. RNA samples from disc tissue and PBMCs were obtained from patients with degenerative discs and from subjects in a control group. RNA samples were reverse-transcribed into Cy5-labeled cRNA, combined with a Cy3-labeled reference and hybridized to oligonucleotide microarrays. Microarrays were scanned by Gene-Pix 4000B and data were analyzed using GenePixPro 3.0 software. The microarray data were validated in the same RNA samples by qRT-PCR analysis of selected genes. For the disc tissue, the mRNA expressions of 522 genes changed obviously in the degeneration group, accounting for approximately 2.64% of all analyzed transcripts. These included transcription-related, ion channel and transport protein, receptor, protein synthesis and modifying, growth factor, etc. For PBMCs, the expressions of 62 genes changed obviously in the patients in the degeneration group. These changes included ion channel, transport protein, transcription-related, DNA synthesis and repair, metalloprotease, immune globulin-related, growth factor-related, extracellular matrix-related, adhesion molecule, etc. Analyzed on the association of the differential expression of genes between disc tissue and PBMCs, some genes were not compatible. The course of intervertebral disc denegation is a complicated dynamic process, however, and may mainly be local pathogenesis. These findings furnish new data for the mechanistic investigation of degenerative discs.

Mesenchymal Stem Cell (MSC)-Derived Extracellular Vesicles: Potential Therapeutics as MSC Trophic Mediators in Regenerative Medicine.

Mesenchymal stem cells (MSCs) are pluripotent progenitor cells with the capabilities of self-renewing, differentiating into multiple lineages, and achieving trophic effects during tissue repair. MSCs can secrete extracellular vesicles (EVs) including exosomes and microvesicles, which mediate their trophic effects on other cells. Carrying a variety of intracellular molecules of MSCs including lipids, proteins, RNA (mRNA and noncoding RNA), and DNA, EVs deliver them into other cells to regulate tissue regeneration process. The therapeutic effects of MSC-derived EVs have been observed in a number of animal disease models. In this review, we focus on the current state and future directions of MSC-derived EVs in regenerative medicine. Anat Rec, 2019. © 2019 Wiley Periodicals, Inc.

Is It Possible to Replace Microendoscopic Discectomy with Percutaneous Transforaminal Discectomy for Treatment of Lumbar Disc Herniation? A Meta-Analysis Based on Recurrence and Revision Rate.

OBJECTIVES: Due to recent developments and the wide application of percutaneous transforaminal discectomy (PTED) in China, we herein compare its clinical effects with microendoscopic discectomy (MED) for the treatment of lumbar disc herniation in terms of recurrence and revision rates. METHODS: Six databases, namely, PubMed, EMBASE, Cochrane Library, Ovid, China National Knowledge Infrastructure and Wanfang, were searched by computer. The literature was screened according to inclusion and exclusion criteria, and the quality of the included literature was evaluated. After extracting the data from the papers, Review Manager 5.2 software (Cochrane Collaboration, Oxford, UK) was applied to analyze these data. Finally, sensitivity and publication bias analyses of the results were conducted. RESULTS: A total of 12 studies consisting of 2400 patients were included in this meta-analysis. A comparison of PTED with MED revealed higher postoperative recurrence and postoperative revision rates for PTED (odds ratio [OR] recurrence, 1.60; 95% confidence interval [CI], 1.01 to 2.53; p=0.05 and OR revision, 1.77; 95% CI, 1.18 to 2.64, p=0.006). CONCLUSION: PTED has a number of advantages because it is a minimally invasive surgery, but its recurrence and revision rates are higher than MED. Therefore, MED should not be completely replaced by PTED.

Association between the -1562 C/T polymorphism of matrix metalloproteinase-9 gene and lumbar disc disease in the young adult population in North China.

Many studies have demonstrated that matrix metalloproteinase-9(MMP-9) is involved in the development of lumbar disc disease (LDD). The expression and activity of MMP-9 are significantly enhanced in degenerative discs. The polymorphism -1562C/T in the promoter region of MMP-9 gene alters the transcriptional activity of this gene. In this study we assessed the relationship between the -1562C/T polymorphism of matrix metalloproteinase-9 gene and the extent of degenerative disc disease in the young adult population in North China. Genotypes were defined by polymerase chain reaction and direct DNA sequencing in 408 young patients with LDD and 451 control subjects. The resulting genotypes were correlated with the presence of lumbar disc degeneration on MRI. The frequency of the MMP-9 -1562T genotype in patients with LDD was significantly higher than in healthy controls. Compared with CC genotype, subjects with the CT/TT genotype had a higher risk to develop LDD (odds ratio 2.14; 95% confidence interval 1.55-2.96). Moreover, an association was found between this genotype and more severe grades of disc degeneration observed on magnetic resonance imaging scan. These results indicated that the -1562C/T polymorphism of the MMP-9 gene is associated with a high risk of degenerative disc disease in the young adult population in North China.

Effects of intermittent negative pressure on osteogenesis in human bone marrow-derived stroma cells.

OBJECTIVE: We investigated the effects of intermittent negative pressure on osteogenesis in human bone marrow-derived stroma cells (BMSCs) in vitro. METHODS: BMSCs were isolated from adult marrow donated by a hip osteoarthritis patient with prosthetic replacement and cultured in vitro. The third passage cells were divided into negative pressure treatment group and control group. The treatment group was induced by negative pressure intermittently (pressure: 50 kPa, 30 min/times, and twice daily). The control was cultured in conventional condition. The osteogenesis of BMSCs was examined by phase-contrast microscopy, the determination of alkaline phosphatase (ALP) activities, and the immunohistochemistry of collagen type I. The mRNA expressions of osteoprotegerin (OPG) and osteoprotegerin ligand (OPGL) in BMSCs were analyzed by real-time polymerase chain reaction (PCR). RESULTS: BMSCs showed a typical appearance of osteoblast after 2 weeks of induction by intermittent negative pressure, the activity of ALP increased significantly, and the expression of collagen type I was positive. In the treatment group, the mRNA expression of OPG increased significantly (P<0.05) and the mRNA expression of OPGL decreased significantly (P<0.05) after 2 weeks, compared with the control. CONCLUSION: Intermittent negative pressure could promote osteogenesis in human BMSCs in vitro.

[Effects of selenium and/or iodine deficiency on chondrocyte apoptosis in rats].

OBJECTIVE: To explore the effects of selenium and/or iodine deficiency on chondrocyte apoptosis in articular cartilage in rats. METHODS: Forty-eight Sprague-Dawley rats were randomly divided into selenium deficiency group, iodine deficiency group, combined selenium and iodine deficiency group, and control group. Chondrocyte apoptosis was detected by terminal deoxynucleotidyl transferase biotin-dUTP nick end labeling (TUNEL) method, and Bcl-2 and Bax in articular cartilage were stained by immunohistochemistry in F3 generation of rats. RESULTS: In articular cartilage, the positive rate of apoptotic chondrocytes stained by TUNEL in the upper and middle zones in selenium deficiency group, iodine deficiency group, and combined selenium and iodine deficiency group (all P < 0.05) were significantly higher than that in control group. The apoptotic chondrocytes were prominent in the middle zone. The positive percentage of chondrocytes apoptosis was not significantly different among these three groups (P > 0.05). Compared with the control group, the expressions of both Bcl-2 and Bax were significantly higher in the upper and middle zone in the selenium deficiency group, iodine deficiency group, and combined selenium and iodine deficiency group (all P < 0.05); however, the expressions of Bcl-2 and Bax were not significantly different among these three groups (P > 0.05). CONCLUSION: Selenium and/or iodine deficiency may induce chondrocyte apoptosis.

Exendin-4 inhibits glioma cell migration, invasion and epithelial-to-mesenchymal transition through GLP-1R/sirt3 pathway.

GLP-1 analogue exendin-4, a glucagon-like peptide 1 receptor (GLP-1R) agonist which shares 53% sequence with GLP-1, plays an essential role in human tumors. However, the function and mechanisms underlying the effects of exendin-4 on glioma cell migration, invasion and epithelial-to-mesenchymal transition are still obscure. Firstly, we demonstrated that GLP-1R was expressed in all glioma cell lines including U87, U251, U373 and A172. Exendin-4 treatment inhibited glioma cell survival, proliferation, migration and invasion. Also, exendin-4 inhibited epithelial-to-mesenchymal transition through positively regulating the expression of E-cadherin (epithelial marker), and negatively regulating the level of Vimentin (mesenchymal marker). Interestingly, we next demonstrated that exendin-4 elevated sirt3 expression dependent on the high level of GLP-1R in U87 and 251 cells. Finally, we confirmed that depletion the level of GLP-1R or sirt3 both reversed the inhibitory action of exendin-4 on glioma cell migration and invasion. These findings demonstrate that exendin-4 treatment suppressed the migration and invasion of glioma cells through GLP-1R/sirt3 pathway and exendin-4 plays an inhibitory effect on glioblastoma cell migration and invasion.