Identification of genes required for the spontaneous repair of partial-thickness cartilage defects in immature rats

Advances in the Treatment of Partial-Thickness Cartilage Defect

Partial-thickness cartilage defects (PTCDs) of the articular surface is the most common problem in cartilage degeneration, and also one of the main pathogenesis of osteoarthritis (OA). Due to the lack of a clear diagnosis, the symptoms are often more severe when full-thickness cartilage defect (FTCDs) is present. In contrast to FTCDs and osteochondral defects (OCDs), PTCDs does not injure the subchondral bone, there is no blood supply and bone marrow exudation, and the nearby microenvironment is unsuitable for stem cells adhesion, which completely loses the ability of self-repair. Some clinical studies have shown that partial-thickness cartilage defects is as harmful as full-thickness cartilage defects. Due to the poor effect of conservative treatment, the destructive surgical treatment is not suitable for the treatment of partial-thickness cartilage defects, and the current tissue engineering strategies are not effective, so it is urgent to develop novel strategies or treatment methods to repair PTCDs. In recent years, with the interdisciplinary development of bioscience, mechanics, material science and engineering, many discoveries have been made in the repair of PTCDs. This article reviews the current status and research progress in the treatment of PTCDs from the aspects of diagnosis and modeling of PTCDs, drug therapy, tissue transplantation repair technology and tissue engineering ("bottom-up").

Effect of Choline on the Composition and Degradation Enzyme of Extracellular Matrix of Mice Chondrocytes Exposed to Fluoride

Choline has been shown to mediate damage of the chondrocyte matrix and degradation enzymes of mice exposed to fluoride (F). To test the action of choline, pregnant mice were treated with differing amounts of F and choline. Newborn mice were weaned at 21 days after birth and treated with the same doses of F and choline as they mothers for 12 weeks. Using hematoxylin-eosin (HE) staining, real-time PCR (RT-PCR), and western blotting, changes in the structure of the cartilage, the expression of mRNA and protein related to proteoglycans (PG), and degradation enzymes were detected. The RT-PCR results show that the expression of the Aggrecan (Acan), transforming growth factor beta (TGF-β1), and Aggrecanases-1 gene were abnormal in the high fluoride (HiF) group, and treatments with choline reversed this phenomenon. The western blotting results show that the protein expression of Aggrecanases-1 was significantly increased in the HiF group (p < 0.01). These findings suggest that F can change the morphology of cartilage tissue, the gene expression of the Acan, TGF-β1, Aggrecanases-1, and the protein expression of the Acan, and that choline can attenuate the effect of F. This may provide the basis for the treatment and prevention of fluorosis.

Articular cartilage and joint development from embryogenesis to adulthood

Within each synovial joint, the articular cartilage is uniquely adapted to bear dynamic compressive loads and shear forces throughout the joint's range of motion. Injury and age-related degeneration of the articular cartilage often lead to significant pain and disability, as the intrinsic repair capability of the tissue is extremely limited. Current surgical and biological treatment options have been unable to restore cartilage de novo. Before successful clinical cartilage restoration strategies can be developed, a better understanding of how the cartilage forms during normal development is essential. This review focuses on recent progress made towards addressing key questions about articular cartilage morphogenesis, including the origin of synovial joint progenitor cells, postnatal development and growth of the tissue. These advances have provided novel insight into fundamental questions about the developmental biology of articular cartilage, as well as potential cell sources that may participate in joint response to injury.