Expression of alpha-smooth muscle actin and contraction of collagen-glycosaminoglycan scaffolds by cells derived from canine synovium
Year: 2003
Type: dissertation
Abstract: Recent studies have demonstrated that several types of musculoskeletal connective tissue cellsincluding chondrocytes, fibrochondrocytes, ligament fibroblasts, osteoblasts, and mesenchymal stem cellscan express the gene for the contractile actin isoform, alpha-smooth muscle actin (SMA), and can contract analogs of extracellular matrix.While the physiological role of the SMA-enabled contraction of these cells remains to be elucidated, such contractility may have detrimental effects when the cells are seeded in scaffolds employed for tissue engineering.These prior findings prompted investigation of SMA expression in synovial cells.These cells have attracted recent interest as donor cells for tissue engineering of articular cartilage because they have been implicated in certain cartilage repair processes in vivo and the chondrogenic potential of the cells has recently been demonstrated in vitro.The objective of this study was to evaluate SMA expression by adult canine synovial cells and their related contraction of collagen-glycosaminoglycan (GAG) analogs of extracellular matrix, as well as cellular proliferation and chondrogenic potential within the scaffolds.Cells from synovial membranes of 6 adult dogs were isolated by outgrowth from the tissue and expanded through seven passages in monolayer culture, with samples from each passage allocated for Western blot analysis of SMA.Cells from passage 4 were seeded into porous type I collagen-GAG matrices and cultured for 4 weeks.The diameters of the cell-seeded scaffolds and non-seeded controls were measured every other day.Synovium-derived cells from the fourth passage were formed into micro-pellets by centrifugation and others seeded into the collagen-GAG matrices, and were incubated in chondrogenic medium with and without fetal bovine serum.After 3 weeks the specimens were prepared for type II collagen immunohistochemistry.Immunohistochemistry revealed the presence of SMA in some cells in the intimal layer of synovium from 4 of the 5 animals analyzed.Western blot analysis demonstrated a regular increase in the amount of SMA in the synovial cells with passage number.The synovial cellmediated contraction of the collagen-GAG scaffolds reached a value of 43% of the original diameter after 4 weeks.This cell-mediated contraction associated with SMA expression was comparable to that found with other musculoskeletal cell types.Incubation of cultures of synovial cells with chondrogenic medium revealed trace amounts of type I collagen production by immunohistochemistry, suggesting that they may be capable of differentiating into chondrocytes.The findings of this study indicate that control of SMA-enabled contraction may be important when employing synovial cells for cartilage repair procedures, and warrant further investigation into the physiological role of SMA expression in synovial cells.
Author: Scott M. Vickers
Language: English
Subfield: Rheumatology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W1529726404