Effects of Muscone on Cartilage Morphology and Matrix Metalloproteinases-3 (MMP-3h) and Matrix Metalloproteinases-9 (MMP-9) Expression in Rheumatoid Arthritis Rat Models

Aim: To discuss Muscone treatment in Rheumatoid Arthritis Rat Models and relative mechanisms. Materials and methods: Dividing 36 rats as 4 groups as Normal, Model, DMSO and Muscone groups (n = 9). Rats of Model, DMSO and Muscone groups were made Rheumatoid Arthritis model. Muscone group were treated with 2 mg/kg Muscone after modeling. HE staining and Masson staining were used to observe the morphological changes of cartilage tissue, measuring MMP-3 and MMP-9 expression by RT-PCR, Western Blotting (WB) and Immunohistochemistry (IHC). Results: Compared with Model group, the pathological changes of Muscone group was significantly improved and average optical density of collagen fibers was significantly depressed (P < 0.001, respectively) via MMP-3 and MMP-9 proteins significantly depressing (P < 0.001, respectively). Conclusion: Muscone improved Rheumatoid Arthritis by depressing MMP-3 and MMP-9 proteins in vivo study.

Anti-degenerative effect of melatonin on intervertebral disc: protective contribution against inflammation, oxidative stress, apoptosis, and autophagy

Intervertebral disc (IVD) degeneration is a leading cause of lower back pain. Although the etiology of IVD degeneration (IVDD) is unclear, excessive oxidative stress, inflammation and apoptosis and disruption of autophagy play important role in the pathogenesis of IVDD. Therefore, finding a solution to mitigate these processes could stop or reduce the development of IVDD. Melatonin, a powerful antioxidant, plays an important role in regulating cartilage tissue hemostasis. Melatonin inhibits destruction of extracellular matrix (ECM) of disc. Melatonin preserves ECM contents including sox-9, aggrecan, and collagen II through inhibiting matrix degeneration enzymes such as MMP-13. These protective effects may be mediated by the inhibition of oxidative stress, inflammation and apoptosis, and regulation of autophagy in IVD cells.

Cartilage Tissue Engineering Approaches Need to Assess Fibrocartilage When Hydrogel Constructs Are Mechanically Loaded

Chondrocytes that are impregnated within hydrogel constructs sense applied mechanical force and can respond by expressing collagens, which are deposited into the extracellular matrix (ECM). The intention of most cartilage tissue engineering is to form hyaline cartilage, but if mechanical stimulation pushes the ratio of collagen type I (Col1) to collagen type II (Col2) in the ECM too high, then fibrocartilage can form instead. With a focus on Col1 and Col2 expression, the first part of this article reviews the latest studies on hyaline cartilage regeneration within hydrogel constructs that are subjected to compression forces (one of the major types of the forces within joints) in vitro. Since the mechanical loading conditions involving compression and other forces in joints are difficult to reproduce in vitro, implantation of hydrogel constructs in vivo is also reviewed, again with a focus on Col1 and Col2 production within the newly formed cartilage. Furthermore, mechanotransduction pathways that may be related to the expression of Col1 and Col2 within chondrocytes are reviewed and examined. Also, two recently-emerged, novel approaches of load-shielding and synchrotron radiation (SR)–based imaging techniques are discussed and highlighted for future applications to the regeneration of hyaline cartilage. Going forward, all cartilage tissue engineering experiments should assess thoroughly whether fibrocartilage or hyaline cartilage is formed.

Intraoperative hyperspectral imaging (HSI) as a new diagnostic tool for the detection of cartilage degeneration

To investigate, whether hyperspectral imaging (HSI) is able to reliably differentiate between healthy and damaged cartilage tissue. A prospective diagnostic study was performed including 21 patients undergoing open knee surgery. HSI data were acquired during surgery, and the joint surface’s cartilage was assessed according to the ICRS cartilage injury score. The HSI system records light spectra from 500 to 1000 nm and generates several parameters including tissue water index (TWI) and the absorbance at 960 nm and 540 nm. Receiver operating characteristic curves were calculated to assess test parameters for threshold values of HSI. Areas with a cartilage defect ICRS grade ≥ 3 showed a significantly lower TWI (p = 0.026) and higher values for 540 nm (p < 0.001). No difference was seen for 960 nm (p = 0.244). For a threshold of 540 nm > 0.74, a cartilage defect ICRS grade ≥ 3 could be detected with a sensitivity of 0.81 and a specificity of 0.81. TWI was not suitable for cartilage defect detection. HSI can provide reliable parameters to differentiate healthy and damaged cartilage. Our data clearly suggest that the difference in absorbance at 540 nm would be the best parameter to achieve accurate identification of damaged cartilage.

Probiotics Composition Harbors Against Osteoarthritis and Inflammation through GABA in Mice

Background: Osteoarthritis (OA) is an age-related disease with multifactorial etiology and its prevalence growing globally. The role of Gut microbiota is inevitable concerning musculoskeletal disease and health. A method of controlling inflammation and cartilage destruction through changes in gut microbiota is proposed. Previously reported data lack the specific approach to microbial clusters and biomarkers in understanding the interactions between host and microbiome.Method: We adopted a novel approach to elaborate the positive influence of S. thermophilus and L. pentosus to treat Anterior cruciate ligament transection (ACLT) induced OA in vivo. For in vitro analysis Human Chondrocyte Cell Line (C28/I2) was used to analyze chondrogenic effect of microbes and GABA. Tukey’s multiple-comparisons test or Two-stage linear step-up procedure of Benjamini, Krieger, and Yekutieli test were used to statistically analyze the data.Results: The gut microbiota-joint axis promoted chondrogenesis and inhibited catabolism. Selected bacteria produced GABA as postbiotic. This study is the first to represent the chondrogenic and protective effects of γ-aminobutyric acid (GABA) on human chondrocytes and cartilage tissue in mice. Oral administration of it down-regulated cartilage degradation in OA-induced mice and decreased inflammation.Conclusion: We speculated the positive results from GABA and probiotics producing GABA against OA. GABA may have functional roles in chondrocyte maturation /differentiation. This data provides a foundation for further studies to elucidate the role of GABA producing microbes and GABA in the regulation of cartilaginous cell proliferation. These findings open future horizons to understand the gut-joint axis and for the treatment of OA. Thus probiotic / GABA therapy could act as a nutraceutical modulator for OA.

Hydrogel composite scaffolds achieve recruitment and chondrogenesis in cartilage tissue engineering applications

Background The regeneration and repair of articular cartilage remains a major challenge for clinicians and scientists due to the poor intrinsic healing of this tissue. Since cartilage injuries are often clinically irregular, tissue-engineered scaffolds that can be easily molded to fill cartilage defects of any shape that fit tightly into the host cartilage are needed. Method In this study, bone marrow mesenchymal stem cell (BMSC) affinity peptide sequence PFSSTKT (PFS)-modified chondrocyte extracellular matrix (ECM) particles combined with GelMA hydrogel were constructed. Results In vitro experiments showed that the pore size and porosity of the solid-supported composite scaffolds were appropriate and that the scaffolds provided a three-dimensional microenvironment supporting cell adhesion, proliferation and chondrogenic differentiation. In vitro experiments also showed that GelMA/ECM-PFS could regulate the migration of rabbit BMSCs. Two weeks after implantation in vivo, the GelMA/ECM-PFS functional scaffold system promoted the recruitment of endogenous mesenchymal stem cells from the defect site. GelMA/ECM-PFS achieved successful hyaline cartilage repair in rabbits in vivo, while the control treatment mostly resulted in fibrous tissue repair. Conclusion This combination of endogenous cell recruitment and chondrogenesis is an ideal strategy for repairing irregular cartilage defects. Graphical Abstract

Effect of passage number of genetically modified TGF-β3 expressing primary chondrocytes on the chondrogenesis of ATDC5 cells in a 3D coculture system

Due to the lack of blood vessels, nerves and lymphatics, articular cartilage is difficult to repair once damaged. Tissue engineering is considered to be a potential strategy for cartilage regeneration. Successful tissue engineering strategies depend on the effective combination of biomaterials, seed cells and biological factors. In our previous study, a genetically modified coculture system with chondrocytes and ATDC5 cells in an alginate hydrogel has exhibited a superior ability to enhance chondrogenesis. In this study, we further evaluated the influence of chondrocytes at various passages on chondrogenesis in the coculture system. The results demonstrated that transfection efficiency was hardly influenced by the passage of chondrocytes. The coculture system with passage 5 (P5) chondrocytes had a better effect on chondrogenesis of ATDC 5 cells, while chondrocytes in this coculture system presented higher levels of dedifferentiation than other groups with P1 or P3 chondrocytes. Therefore, P5 chondrocytes were shown to be more suitable for the coculture system, as they accumulated in sufficient cell numbers with more passages and had a higher level of dedifferentiation, which was prone to form a favorable niche for chondrogenesis of ATDC5 cells. This study may provide fresh insights for future cartilage tissue engineering strategies with a combination of a coculture system and advanced biomaterials.

Three-Dimensional Printing Strategies for Irregularly Shaped Cartilage Tissue Engineering: Current State and Challenges

Although there have been remarkable advances in cartilage tissue engineering, construction of irregularly shaped cartilage, including auricular, nasal, tracheal, and meniscus cartilages, remains challenging because of the difficulty in reproducing its precise structure and specific function. Among the advanced fabrication methods, three-dimensional (3D) printing technology offers great potential for achieving shape imitation and bionic performance in cartilage tissue engineering. This review discusses requirements for 3D printing of various irregularly shaped cartilage tissues, as well as selection of appropriate printing materials and seed cells. Current advances in 3D printing of irregularly shaped cartilage are also highlighted. Finally, developments in various types of cartilage tissue are described. This review is intended to provide guidance for future research in tissue engineering of irregularly shaped cartilage.

Perichondrial progenitor cells promote proliferation and chondrogenesis of mature chondrocytes

Autologous chondrocytes are effective sources of cell therapy for engineering cartilage tissue to repair chondral defects, such as degenerative arthritis. The expansion of cells with chondrocyte characteristics has become a major challenge due to inadequate donor sites and poor proliferation of mature chondrocytes. The perichondrial progenitor cells (P cells) from the cambium layer of the perichondrium possessed significantly higher mesenchymal stem cell markers than chondrocytes (C cells). In the transwell co-culture system, P cells increased the passaging capacity of C cells from P6 to P9, and the cell number increased 128 times. This system increased the percentage of Alcian blue-positive chondrocytes from 40% in P6 to 62% in P9, contributing about 198 times more Alcian blue-positive chondrocytes than the control group. C cells co-cultured with P cells also exhibited higher proliferation than C cells cultured with P cell-conditioned medium. Similar results were obtained in nude mice that were subcutaneously implanted with C cells, P cells, or a mixture of the two cell types, in which the presence of both cells enhanced neocartilage formation in vivo. In aggregate, P cells enhanced the proliferation of C cells in a dose-dependent manner and prolonged the longevity of mature chondrocytes for clinical applications.