PubMed · 16149651
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Hideto Watanabe. 2005. [Aggrecan].. https://pubmed.ncbi.nlm.nih.gov/16149651/
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Tissue engineering strategies, based on developing three-dimensional scaffolds capable of transferring autologous chondrogenic cells, holds promise for the restoration of damaged cartilage. In this study, the authors aimed at determining whether a recently developed silanized hydroxypropyl methylcellulose (Si-HPMC) hydrogel can be a suitable scaffold for human nasal chondrocytes (HNC)-based cartilage engineering. Methyltetrazolium salt assay and cell counting experiments first revealed that Si-HPMC enabled the proliferation of HNC. Cell tracker green staining further demonstrated that HNC were able to form nodular structures in this three-dimensional scaffold. HNC phenotype was then assessed by RT-PCR analysis of type II collagen and aggrecan expression as well as alcian blue staining of extracellular matrix. Our data indicated that Si-HPMC allowed the maintenance and the recovery of a chondrocytic phenotype. The ability of constructs HNC/Si-HPMC to form a cartilaginous tissue in vivo was finally investigated after 3 weeks of implantation in subcutaneous pockets of nude mice. Histological examination of the engineered constructs revealed the formation of a cartilage-like tissue with an extracellular matrix containing glycosaminoglycans and type II collagen. The whole of these results demonstrate that Si-HPMC hydrogel associated to HNC is a convenient approach for cartilage tissue engineering.
A source of morphologically and functionally available human cartilagenous tissue for implantation is required in the field of tissue engineering. To achieve this goal, we evaluated the effects of hyaluronic acid (HA-810 and 1680 kDa), and chondroitin sulfate (CS-A 16 and C-34 kDa) on human articular chondrocytes (HC) in micromass and rotation culture conditions. Cell proliferation was increased by CS-A 16 kDa under micromass and rotation cultures, while cell differentiation was increased under rotation but not micromass conditions. Proliferation and differentiation due to CS-C 34 kDa were very similar to the control under both culture conditions. With HA, cell proliferation was increased depending on the molecular weight under micromass and rotation conditions. In contrast, chondrocyte differentiation was enhanced under rotation conditions, but decreased under micromass conditions depending on the molecular weight of HA. In both culture conditions, aggrecan gene was continuously expressed. However, the collagen type II gene was more weakly expressed in rotation than the micromass culture conditions. Thus, the chemical structures of polysaccharides, and the culture condition, rotation or micromass, caused differences in chondrogenesis.
Middiaphyseal femoral fractures in children and young rats stimulate linear femoral growth, a phenomenon commonly attributed to increased vascularity. To test for changes in mRNA expression of genes related to blood vessels, nerve fibers, cartilage, bone, and cell metabolism, we measured mRNA gene expression for all known rat genes in the physis at various times after diaphyseal fracture. Female Sprague-Dawley rats, 4 weeks of age at surgery, were subjected to a unilateral, simple, transverse, middiaphyseal femoral fracture stabilized with an intramedullary rod. At 0 (intact), 0.1, 0.4, 1, 2, 3, 4, and 6 weeks after fracture, the femoral head with the proximal physis was collected from fractured and intact femora. The RNA was extracted, processed to biotinlabeled cRNA, and hybridized to Affymetrix Rat 230 2.0 GeneChip microarrays. Transcripts from fracture-induced lengthening of the injured femora were compared to those of the intact contralateral femur. In the proximal physis, transcripts related to blood vessels and cartilage formation were down-regulated by fracture. Transcripts related to bone remodeling, nerve axon elongation, cell division, and protein synthesis were up-regulated by fracture. The data support increased mitotic activity in the physis after a midshaft fracture and not increased vascularity.