[Effect and mechanism of ultraviolet-cross-linkable chitosan-carbon dots-morin hydrogel treating for rat cartilage injury].

Objective: To construct a ultraviolet-cross-linkable chitosan-carbon dots-morin (NMCM) hydrogel, observe whether it can repair cartilage injury by in vivo and in vitro experiments, and explore the related mechanism. Methods: The chitosan was taken to prepare the ultraviolet (UV)-cross-linkable chitosan by combining methacrylic anhydride, and the carbon dots by combining acrylamide. The two solutions were mixed and added morin solution. After UV irradiation, the NMCM hydrogel was obtained, and its sustained release performance was tested. Chondrocytes were separated from normal and knee osteoarticular (KOA) cartilage tissue donated by patients with joint replacement and identified by toluidine blue staining. The 3rd generation KOA chondrocytes were co-cultured with the morin solutions with concentrations of 12.5, 25.0, 50.0 µmol/L and NMCM hydrogel loaded with morin of the same concentrations, respectively. The effects of morin and NMCM hydrogel on the proliferation of chondrocytes were detected by cell counting kit 8 (CCK-8). After co-cultured with NMCM hydrogel loaded with 50 µmol/L morin, the level of collagen type Ⅱ (COL-Ⅱ) of KOA chondrocytes was detected by immunofluorescence staining, and the level of reactive oxygen species (ROS) was detected by 2, 7-dichlorodihydrofluorescein diacetate (DCFH-DA) probe. Twenty 4-week old Sprague Dawley rats were selected to construct a articular cartilage injury of right hind limb model, and were randomly divided into two groups ( n=10). The cartilage injury of the experimental group was repaired with NMCM hydrogel loaded with 25 µmol/L morin, and the control group was not treated. At 4 weeks after operation, the repair of cartilage injury was observed by micro-CT and gross observation and scored by the International Cartilage Repair Association (ICRS) general scoring. The cartilage tissue and subchondral bone tissue were observed by Safranine-O-fast green staining and COL-Ⅱ immunohistochemistry staining and scored by ICRS histological scoring. The expressions of tumor necrosis factor α (TNF-α), nuclear factor κB (NK-κB), matrix metalloproteinase 13 (MMP-13), and COL-Ⅱ were detected by Western blot and real-time fluorescence quantitative PCR. Results: NMCM hydrogels loaded with different concentrations of morin were successfully constructed. The drug release rate was fast in a short period of time, gradually slowed down after 24 hours, and the amount of drug release was close to 0 at 96 hours. At this time, the cumulative drug release rate reached 88%. Morin with a concentration ≤50 µmol/L had no toxic effect on chondrocytes, and the proliferation of chondrocytes improved under the intervention of NMCM hydrogel ( P<0.05). NMCM hydrogel loaded with morin could increase the level of COL-Ⅱ in KOA chondrocytes ( P<0.05) and reduce the level of ROS ( P<0.05), but it did not reach the normal level ( P<0.05). Animal experiments showed that in the experimental group, the articular surface was rough and the defects were visible at 4 weeks after operation, but the surrounding tissues were repaired and the joint space remained normal; in the control group, the articular surface was rougher, and no repair tissue was found for cartilage defects. Compared with the control group, the experimental group had more chondrocytes, increased COL-Ⅱ expression, and higher ICRS gross and histological scores ( P<0.05); the relative expressions of MMP-13, NF-κB, and TNF-α protein and mRNA significantly decreased ( P<0.05), and the relative expressions of COL-Ⅱ protein/COL-2a1 mRNA significantly increased ( P<0.05). Conclusion: NMCM hydrogel can promote chondrocytes proliferation, down regulate chondrocyte catabolism, resist oxidative stress, protect chondrocytes from cartilage injury, and promote cartilage repair.

LncRNA BACE1-AS promotes the progression of osteosarcoma through miR-762/SOX7 axis.

BACKGROUND: Osteosarcoma (OS) is a rare malignant primary tumor of mesenchymal origin affecting bone that occurs in adolescents and children. LncRNAs are important regulators of tumorigenesis and development. This study aimed to explore the role and molecular basis of LncRNA BACE1-AS (BACE1 antisense RNA) in OS. METHODS AND RESULTS: Through the analysis of differential expressed lncRNAs in OS tissues by GEO database, LncRNA BACE1-AS display a remarkably lower expression. This found can also be observed in both OS tissues and cell lines by qRT-PCR. Furthermore, using Cell counting kit-8 (CCK-8), transwell, wound healing and westernblot assays, overexpression LncRNA BACE1-AS remarkably reduce cell proliferation, migration and invasion abilities in OS. In addition, LncRNA BACE1-AS is validated as a sponge of miR-762 through the prediction of lncRNASNP. Further, luciferase reporter and RIP assays are conducted to confirm the binding sites between LncRNA BACE1-AS and miR-762. SRY-box transcription factor 7 (SOX7) target to miR-762 and regulated by LncRNA BACE1-AS. Moreover, inhibition of miR-762 attenuate the role of sh-LncRNA BACE1-AS in OS cells, at meanwhile reduce the expression of SOX7. CONCLUSION: In this study, LncRNA BACE1-AS regulates proliferation, migration and invasion of osteosarcoma cells by miR-762/SOX7 axis, implying that LncRNA BACE1-AS is a potential target for osteosarcoma therapy.

Morin Exhibits Anti-Inflammatory Effects on IL-1ß-Stimulated Human Osteoarthritis Chondrocytes by Activating the Nrf2 Signaling Pathway.

BACKGROUND/AIMS: Osteoarthritis (OA) is a multifactorial disease that is associated with inflammation in joints. The purpose of the present study was to investigate the anti-inflammatory activity and mechanism of morin on human osteoarthritis chondrocytes stimulated by IL-1ß. METHODS: The levels of NO and PGE2 were measured by the Griess method and ELISA. The levels of MMP1, MMP3, and MMP13 were also measured by ELISA. RESULTS: The results revealed that IL-1ß significantly increased the production of NO, PGE2, MMP1, MMP3, and MMP13. Additionally, the increases were significantly attenuated by treatment with morin. Furthermore, IL-1ß-induced NF-κB activation was suppressed by morin. In addition, the expression of Nrf2 and HO-1 were increased by morin and knockdown of Nrf2 could prevent the anti-inflammatory effects of morin. CONCLUSION: In conclusion, this study suggested that morin attenuated IL-1ß-induced inflammation by activating the Nrf2 signaling pathway.

Growth differentiation factor­5 induces tenomodulin expression via phosphorylation of p38 and promotes viability of murine mesenchymal stem cells from compact bone.

Growth differentiation factor (GDF)­5 serves a role in tissue development and tenomodulin serves an important role in the development of tendons. The effects of GDF­5 on mesenchymal stem cells (MSCs), particularly with regards to tendon bioengineering, are poorly understood. The present study aimed to investigate the effects of GDF­5 on cell viability and tenomodulin expression in MSCs from murine compact bone. MSCs were isolated from murine compact bones and confirmed by flow cytometric analysis. In addition, the adipogenic, osteoblastic and chondrocyte differentiation capabilities of the MSCs were determined. MSCs were treated with GDF­5 and the effects of GDF­5 on MSC viability were determined. The mRNA and protein expression levels of tenomodulin were detected by reverse transcription­quantitative polymerase chain reaction and western blotting, respectively. MSCs from murine compact bone were successfully isolated. GDF­5 had optimal effects on cell viability at 100 ng/ml (+36.9% of control group without GDF­5 treatment, P<0.01) and its effects peaked after 6 days of treatment (+56.6% of control group, P<0.001). Compared with the control group, treatment with 100 ng/ml GDF­5 for 4 days enhanced the mRNA expression levels of tenomodulin (3.56±0.94 vs. 1.02±0.25; P<0.05). In addition, p38 was activated by GDF­5, as determined by enhanced expression levels of phosphorylated p38 (p­p38). The GDF­5­induced protein expression levels of p­p38 and tenomodulin were markedly inhibited following treatment with SB203580, an inhibitor of p38 mitogen­activated protein kinase. These results suggested that GDF­5 treatment may increase tenomodulin protein expression via phosphorylation of p38 in MSCs from murine compact bone. These findings may aid the future development of tendon bioengineering.

Mangiferin Inhibits IL-1ß-Induced Inflammatory Response by Activating PPAR-γ in Human Osteoarthritis Chondrocytes.

Inflammation has been reported to play critical roles in the development of osteoarthritis. In the present study, we investigated whether mangiferin (MFN) had anti-inflammatory effects in IL-1ß-stimulated human osteoarthritis chondrocytes. The cells were treated with various concentrations of MFN in the presence or absence of IL-1ß. The production of MMP-1, MMP-3, PGE2, and NO was measured in this study. The expression of NF-kB and PPAR-γ was detected by western blot analysis. MFN inhibited IL-1ß-induced inflammatory mediators PGE2 and NO production. MFN also inhibited IL-1ß-induced MMP1 and MMP3 production. IL-1ß-induced NF-kB activation was significantly inhibited by MFN. In addition, MFN was found to up-regulate the expression of PPAR-γ in human osteoarthritis chondrocytes. PPAR-γ inhibitor GW9662 significantly reversed the anti-inflammatory effects of MFN. These results suggest that MFN inhibits IL-1ß-induced inflammatory response in human osteoarthritis chondrocytes by activating PPAR-γ.

Effects of platycodin D on IL-1ß-induced inflammatory response in human osteoarthritis chondrocytes.

Platycodin D (PYD), a major saponin derived and isolated from the roots of Platycodon grandiflorum, has been reported to have anti-inflammatory and anti-tumor effects. The present study aimed to investigate the effects of PYD on IL-1ß-stimulated human osteoarthritis chondrocytes. Chondrocytes were treated with PYD 1h before IL-1ß treatment. The levels of MMP1, MMP13, IL-8, RANTES, PGE2, and NO were measured in this study. The expression of LXRα, NF-κB, and IκBα were detected by western blot analysis. The results showed that PYD significantly inhibited IL-1ß-induced MMP1, MMP13, IL-8, RANTES, PGE2, and NO production. PYD also suppressed IL-1ß-induced NF-κB activation. Furthermore, the expression of LXRα was up-regulated by PYD in a dose-dependent manner. In addition, LXRα siRNA inhibited the effects of PYD on MMP1, MMP13, PGE2, and NO production in human osteoarthritis chondrocytes. In conclusion, these results suggested that PYD attenuated IL-1ß-induced inflammatory response in osteoarthritis chondrocyte by activating LXRα.

[Application of modified traction arch of skull in skull traction].

OBJECTIVE: To investigate the feasibility and effectiveness of the modified traction arch of skull (crossbar traction arch) for skull traction in treating cervical spine injury by comparing with traditional traction arch of skull. METHODS: Between June 2009 and June 2013, 90 patients with cervical vertebrae fractures or dislocation were treated with modified skull traction surgery (trial group, n=45) and traditional skull traction surgery (control group, n=45). There was no significant difference in gender, age, injury types, injury level, the interval between injury and admission, and Frankel grading of spinal injury between 2 groups (P > 0.05). The clinical efficacy was evaluated after operation by the indexes such as traction arch slippage times, operation time, the infection incidence of the pin hole, incidence of skull perforation, visual analogue scale (VAS), and reduction status of cervical dislocation. RESULTS: The traction arch slippage times, the infection incidence of the pin hole, operation time, blood loss, and postoperative VAS score in trial group were significantly lower than those in control group (P < 0.05). There was no significant difference in the incidence of skull perforation caused by clamp crooks of traction arch between 2 groups (P=1.000). At 2 weeks after operation, the patients had no headaches, infections, or other complications in 2 groups. In patients with cervical dislocation, 4 of the trial group and 6 of the control group failed to be reset, the reduction rate was 83.33% (20/24) and 68.42% (13/19) respectively, showing no significant difference (χ2=0.618, P=0.432). CONCLUSION: The operation with modified traction arch of skull has significant advantages to reduce postoperative complication compared with tradition traction arch of skull.

[Current situation and prospect of tenomodulin in tendon tissue engineering].

OBJECTIVE: To review the latest researches of Tenomodulin in tendon tissue engineering, to predict the progress of research and application of Tenomodulin. METHODS: The literature concerning Tenomodulin in tendon tissue engineering was collected and analyzed. RESULTS: Tenomodulin is a type II transmembrane glycoprotein that can regulate growth of tendon and contains a C-terminal anti-angiogenic domain. The human Tenomodulin gene spans approximately 1360 bp and is mapped to Xq22.1. The expression of Tenomodulin is regulated by various biological factors, especially Scleraxis; and the nature and structure of scaffold material as well as the stain loading and cell passage, can modulate the expression of Tenomodulin. CONCLUSION: Tenomodulin, as relatively specific molecule makers for tendon and containing a C-terminal anti-angiogenic domain, is expected to play a significant role in tendon tissue engineering.

[Study on the effect of bone-cement interface with bone cement oscillator].

OBJECTIVE: To evaluate the effect on increasing bone cement-bone interface micro-gomphosis intensity with bone cement oscillator. METHODS: One hundred femoral bones of adult pig were randomly divided into 6 groups: oscillating group (A1) and control group (A2) of anti-tensile force, oscillating group (B1) and control group (B2) of anti-pressure (n = 20 in each group), oscillating group (C1) and control group (C2) of imaging (n = 10 in each group). Mechanics and CT test was performed, micro-gomphosis intensity of bone cement-bone interface between oscillating group and control group was compared. RESULTS: Mechanics and CT test showed bone cement-bone interface micro-gomphosis intensity in oscillating group was significantly stronger than control group (P < 0.01). CONCLUSION: Bone cement oscillator can significantly increase micro-gomphosis intensity of bone-cement interface, and reduce long-term aseptic loosening of artificial prostheses.

Histological study of surface modified three dimensional poly (D, L-lactic acid) scaffolds with chitosan in vivo.

Biocompatibility and tissue regenerating capacity are essential for biomaterials that used in tissue engineering. The aim of this study was to histologically assess the tissue reactions and bone conductivities of surface modified three dimensional (3-D) poly (D, L-lactic acid) (PDLLA) scaffolds, which were coated with chitosan via a physical entrapment method. The native PDLLA scaffold was prepared via thermally induced phrase separation technique and was characterized by scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Osteocalcin assay, a method to evaluate the bone formation potential, has shown that the osteocalcin production in chitosan-modified 3-D PDLLA scaffold group was significantly higher (p < 0.05) than that of in control. The tissue reactions and bone conductivities between surface modified PDLLA and native PDLLA scaffolds were evaluated using a rabbit radialis defect model in vivo and compared at different implantation intervals (2, 4, 8 and 12 weeks). The histological results have shown a higher bone formation potential and better biocompatibility of chitosan-modified 3-D PDLLA scaffolds as compared with the control group scaffolds.